Environmental Factors Affecting Language Acquisition from Birth – Five:

Implications for Literacy Development and Intervention Efforts

David K. Dickinson

Jill B. Freiberg

Vanderbilt University’s Peabody College

Prepared for the Committee on the Role of Language in School Learning

Draft Version

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Language acquisition is one of the miracles of early development and extensive effort has been

expended attempting to understand how young children come to acquire such a complex system so

quickly. Recently, as scholars have begun to examine the emergence of literacy, it has become clear that

there are powerful continuities between early language learning and later academic success and

realization that factors such as poverty place children at elevated risk for acquiring language skills

associated with later reading. This realization has fueled efforts to intervene with high risk populations. In

this report we begin by reviewing evidence of the importance of language to literacy, the association

between the birth – five period and later literacy, and then discuss experiences during the birth-to-five

years that are associated with enhanced growth and the effectiveness of interventions designed to enhance

language learning. Much of the available research focuses on children whose first language is English,

but new studies are beginning to explore early language learning of children who are acquiring more than

one language. We discuss this work and what is known about interventions designed to facilitate their

development.

Language and Early Literacy, Birth - Five

Language-Reading Relationships

By the middle to later elementary school years reading comprehension, the reading skill that

matters for long-term academic success, is highly dependent on language abilities. This dependency is at

the core of leading theories of reading development, the Simple View (Hoover & Gough, 1990) and the

recent Convergent Skills Model of Reading (CSMR) (Vellutino, Tunmer, Jaccard, & Chen, 2007). Both

stress the importance of language skill to comprehension and, drawing on findings of many prior studies,

the CSMR hypothesizes that there is a shift in the importance of different language abilities as children

move from early stages of reading toward becoming skilled readers. Initially, as basic decoding ability is

mastered, phonemic awareness, the ability to attend to phonemes, is of major importance because it

facilitates the mapping of sound units onto graphemes (Ehri, et al., 2001). As decoding skills are

established semantic and syntactic abilities that support language comprehension become of primary

importance to predicting reading comprehension. Data collected to test the CSMR are supportive of the

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theory except that semantic knowledge was found to be equally important at both ages rather than

increasing in importance over time. This finding suggests that the conceptual knowledge that is

associated with complete understanding of words makes an important contribution to reading even when

children are refining basic decoding skills.

Most often studies examining the contribution of language ability to reading ability have used

measures of receptive vocabulary to describe language ability and have found that vocabulary is related to

reading comprehension (National Reading Panel, 2000). The measures used to assess vocabulary are

highly reliable predictors of academic success and therefore are important for gauging children’s access

to the language abilities required for academic success in schools in the United States. They are not

devised to assess the full range of children’s vocabulary. This is important to bear in mind, especially

with respect to vocabulary, because the home language and discourse practices of middle-class well-

educated families are likely to be better aligned with language and vocabulary assessed by standardized

tools. But vocabulary is only one element of the full language system and assessments of it provide only a

partial picture of language ability (Dickinson, McCabe, Anastasopoulos, Peisner-Feinberg, & Poe, 2003).

Broader measures of semantic knowledge such as were used in the test of the CSMR, of syntactic

knowledge (Nation, Clarke, Marshall, & Durand, 2004; Share & Leikin, 2004), and extended discourse

skills such (e.g., narratives, explanations) (Dickinson & Tabors, 2001; O'Neill, Pearce, & Pick, 2004) not

only play an important role predicting later literacy, but may be stronger long-term predictors than

receptive vocabulary (National Early Literacy Panel, 2008). Advanced reading comprehension also is

associated with the ability to become aware of different aspects of language. Phonemic awareness has

long been recognized as being of critical importance as children learn to “crack the code” by associating

letters with sounds (Stanovich, 1986; Torgesen, Wagner, Rashotte, Burgess, & Hecht, 1997; Wagner &

Torgesen, 1987). Skilled reading also has been found to be associated with morphological awareness, an

awareness of the units of meaning within words (Deacon & Kirby, 2004; Nation, et al., 2004).

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Thus, several decades of research on reading comprehension have found strong associations

between reading comprehension and multiple dimensions of language skill and metalinguistic abilities.

Questions central to the current report are:

1. Do language abilities in the preschool years predict these later language skills that are associated with

reading comprehension?

2. What experiences in the lives of young children predict the rate of development of these language

abilities that are related to later reading?

3. Are patterns of association between experience and language abilities similar for children who are

learning a new language?

4. What interventions foster enhanced growth of literacy-related language abilities?

Associations Between Early Language and Later Language and Reading

Long-term. There is a growing body of literature linking preschool vocabulary to later reading

skill (National Early Literacy Panel, 2008). Storch and Whitehurst (Storch & Whitehurst, 2002) followed

626 children from low-income homes from age 4 through fourth grade and found that preschool language

skills had a large indirect effect on reading comprehension in grades 3 and 4. The NICHD Child Care

study followed 1,137 children from age 3 to grade 3 and found that age 3 language correlated highly with

grade 3 language (r = .73) and had substantial indirect effects of age 3 language on grade 3 reading

(NICHD Early Child Care Research Network, 2002). Similarly, Dickinson and Tabors (Dickinson &

Tabors, 2001) found that kindergarten vocabulary and word recognition skills, in combination with

children’s rate-of-growth on these measures accounted for over two-thirds of the variance in fourth grade

reading comprehension (Tabors, Porche, & Ross, 2003).

Measures of language competence other than vocabulary also reveal preschool competencies that

predict later language and reading abilities. One study followed low-income children from age 3 to grade

3 and found that age 3 mean length of utterance and diversity of words by children related to kindergarten

and grade 3 measures of general language, spelling and reading after controlling for SES and school

attended (Walker, Greenwood, Hart, & Carta, 1994). More recently a study of four-year old children who

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were followed for two years found that age 4 language predicted grade 2 reading comprehension, with

grammatical knowledge accounting for more variance than vocabulary (Muter, Hulme, Snowling, &

Stevenson, 2004). Detailed long-term studies of language-literacy associations have been conducted by

researchers interested in children who experience early language learning problems. Such studies find

that early language learning problems portend later literacy challenges (Scarborough, 2001), with the

nature of the language problem varying by age. In a recent study of later talkers Rescorla (2009) found

that age 2 vocabulary explained 17% of the variance in the age 17 measures of vocabulary, grammar and

verbal memory.

Birth-Age Five. Language is a complex system that develops rapidly in the early years. Early

language-related processing skills and linguistic knowledge affect later language acquisition and recent

evidence suggests that there are reciprocal relationships between early literacy abilities and language. For

example, the emergence of phonemic awareness is in part a by-product of early vocabulary development

because during the preschool years the size of a child’s vocabulary is associated with improvements in

ability to attend to the sounds of language (Munson, Kurtz, & Windsor, 2005; Storkel, 2001, 2003).

Given that phonemic awareness is a potent predictor of early reading success, the finding that vocabulary

size in preschool fosters its emergence underscores the importance of early language growth to later

reading.

The rate at which young children acquire vocabulary is conditioned by other language abilities.

For example, children use syntactic cues to help detect the meanings of words and the ability to use

syntax to determine meaning varies and children with weaker language skills have more difficulty

employing syntactic cues to learn new words (Kemp, Lieven, & Tomasello, 2005). Another indication of

how early language bolsters later acquisition is the finding that the rate at which children learn new words

is partially conditioned by how many words a child already knows. Children learn new words faster

when words are similar to those already in the child’s lexicon (Storkel, 2003). The practical importance

of this finding is seen when intervention studies use book reading to build vocabulary knowledge and find

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that children with stronger vocabularies are more able to learn words that are presented as part of these

interventions (Penno, Wilkinson, & Moore, 2002).

Evidence that language is an evolving self-reinforcing system extends into the prelinguistic

period. The language comprehension ability and the inclination of 14-month-old toddlers to use gestures

to communicate predict their subsequent expressive and receptive vocabulary (Watt, Wetherby, &

Shumway, 2006). This evidence of continuity between prelinguistic communication efforts and later

language and suggests that early encouragement to communicate may have beneficial effects. Additional

evidence of the importance of the earliest phases of language acquisition to later learning comes from the

finding that very young children’s capacity to quickly interpret language is related to early vocabulary

and language acquisition (Fernald, Perfors, & Marchman, 2006). Early processing ability and related

language have long-term effects because language processing speed and receptive vocabulary size at age

25 months are predictive of vocabulary when children are eight years old (Marchman & Fernald, 2008).

A meta-analysis of preschool predictors of later reading also found that speed of processing reliably

predicts later reading (National Early Literacy Panel, 2008).

In sum, multiple facets of language ability lay the foundation for subsequent language and

reading abilities. During the years between birth and five early language competencies facilitate

subsequent acquisition suggesting that language is a self-reinforcing system that gains momentum during

the preschool years. Evidence is not available that links specific types of preschool language competence

to later literacy outcomes, but considerable evidence points to the importance of the rate at which children

acquire language. Furthermore, children with a strong early language learning trajectory are at an

advantage because, unless a child has a specific language deficiency (Gray, 2005; Johnson & deVilliers,

2009; Nash & Donaldson, 2005), multiple emerging language systems work in concert to facilitate rapid

vocabulary acquisition. We now turn to consideration of how environmental factors influence the rate and

course of language learning.

Environmental Influences on Language Learning

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The finding that early language abilities play an important role in determining later reading and

associated academic success raises the question of the extent to which reading is determined by genetic

factors as opposed to variability in children’s experiences. One way to address this question is to study

identical and fraternal twins. A study of 7,179 twins found that language development and reading ability

are largely determined by environmental factors (Harlaar, Hayiou-Thomas, Dale, & Plomin, 2008).

Another twin study of early vocabulary and expressive language learning also found that environmental

factors accounted for between 54% and 78% of the variation (Van Hulle, Goldsmith, & Lemery, 2004),

further highlighting the need to identify environmental factors associated with enhanced language

learning.

Some current theories of how children acquire language stress the interplay between biologically

determined perceptual and cognitive processing mechanisms, physical and social environmental cues and

prior learning (Hirsch-Pasek, Golinkoff, Hennon, & Maguire, 2004; Lidz, Gleitman, & Gleitman, 2004;

Waxman, 2004). The Emergentist Convergent Coalition (Golinkoff & Hirsh-Pasek, 2008; Hirsh-Pasek &

Michnick Golinkoff, 2008) argues that the child first draws on biologically-driven attention mechanisms,

begins to use social cues provided by conversational partners at an early age as well as language-learning

hypotheses, and then as acquisition gains momentum, draws on existing lexical and grammatical

knowledge. An implication of this theory is that language learning is the result of the orchestration of an

impressive panoply of resources that are progressively honed into an efficient language learning

mechanism. This view of language acquisition as being progressive determined by children’s agile use of

linguistic input implies that, as they near the age of school entrance, children may vary not only in

linguistic sophistication but also in their facility with learning language.

Socio-economic status. Socio-economic status is a consistent predictor of variability in the rate of

acquisition of vocabulary, complex grammar and skill using language for varying purposes (Hoff, 2006).

Variables associated with SES such as income, education, race, ethnicity, and home language covary,

making it hard to disentangle their effects. The NICHD Child Care study, a major longitudinal study of

children from varied social and economic backgrounds was able to disentangle some of these by virtue of

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having a very large sample that included collection of a host of measures describing homes, parents and

health status. This sample, that included only parents who spoke English, provided information about the

impact of home and child care experiences starting at six months on language and on children’s later

cognitive and social development. Analysis of the effects of poverty on a broad measure of language

development during the preschool years revealed a moderate sized effect of d = .47 (NICHD Early Child

Care Research Network, 2002), with poverty being associated with lower scores. This finding is

consistent with other studies that have found that persistent poverty has particularly deleterious effects on

early development and that the effects of poverty during the preschool years are most likely to have

negative effects on children’s development (Britto, Fuligni, & Brooks-Gunn, 2006).

Syntactic development also is related to parental background (Hoff, 2006). Examination of

syntactic development between 22 and 42 months of children from various SES backgrounds found that,

whereas all children showed roughly similar profiles of development in use of simple syntactic forms,

those from the lowest economic backgrounds displayed substantially slower development in use of

complex syntax (Vasilyeva, Waterfall, & Huttenlocher, 2008).

Substantial differences in the rate of vocabulary learning are associated with SES (Hoff, 2006),

with differences in rate of acquisition found to be associated with variation in the amount of exposure, the

density of novel words relative to all words used, and the syntactic complexity of input provided (Hoff &

Naigles, 2002). The size of differences between children from families of poverty is made apparent by

data from a nationally representative sample of four year olds who were tested at entry to Head Start

using the Peabody Picture Vocabulary test (Dunn & Dunn, 1997). The average score for these children

was roughly a standard deviation below national samples; in raw scores, this is a score that would be

achieved by a child who is 2;10 who performed at the national average (Zill & Resnick, 2006). A study of

language learning rates of children found that in second grade children from economically advantaged

homes knew 6,200 words compared with children from mixed SES backgrounds who knew 5,200. Most

troubling was the fact that children in the lowest quartile of the mixed SES sample knew only 4,000

words (Biemiller & Slonim, 2001). Between grades 3 – 5 children from the mixed SES group added

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3,200 new words while those in the advantaged group learned 2,500. Thus, the vocabulary gap began to

close as children begin to read, but those who entered with depressed vocabulary scores remained behind

their peers. Results from the Early Childhood Longitudinal Study (ECLS-K), a nationally representative

longitudinal study, indicate that differences in reading seen at the beginning of kindergarten associated

with poverty increase by the end of first grade as does the gap between black and white children after

controlling for poverty and gender (Chatterji, 2006). In contrast, when income and gender are controlled,

Hispanic children nearly catch up with their white counterparts.

The widely cited study by Betty Hart and Todd Risley (Hart & Risley, 1995) describes in

concrete detail how language learning relates to income. They observed the home language experiences

of children from different backgrounds from when they were 12 months old until they were 36 months

old. At 30 months they estimated that children from economically advantaged homes had productive

vocabularies of 766 words and children from low-income homes had productive vocabularies of 357

words. At age 36 months all children’s productive vocabularies grew by roughly 50%; economically

advantaged children gained 350 new words and those from low-income homes added 168 words. Despite

growing at roughly comparable rates, the children from less lexically-enriched homes had language gains

that were less than ½ those of their peers. These differences reflected vast differences in the total amount

of language exposure of these children. By age three, the children from homes with highly educated and

affluent parents heard 30 million more words than did children living in homes where their parents were

poor and had limited education.

Race and ethnicity. By fourth grade scores on the National Assessment of Educational Progress

(NAEP) reveal that race, ethnicity and language background are related to sizable differences in

children’s reading performance (Campbell, Hombo, & Mazzeo, 2000). However, in contrast to the

analysis of the ECLS-K data by Chatterji (2006), these results have not been analyzed using methods that

control for the confounding effects of poverty. NAEP data indicate that children from Caucasian families

consistently outperformed Hispanic children and Black, non-Hispanic children, with this gap being

essentially the same in 2007 (National Center for Education Statistics, 2009). This achievement gap is

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already present at school entry as indicated by results from the Early Childhood Longitudinal Survey

(National Center for Education Statistics, 2006). When children entered kindergarten those classified as

“white” outperformed children from Hispanic homes who, in turn out-performed African-American

children. This relative ranking remained constant through fifth grade, with the distance between groups

increasing. Furthermore, data from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) that

followed children from birth to school entry, found sizable race and ethnicity-related differences in the

vocabulary knowledge of four year old children, with Black non-Hispanic children performing more

poorly that white children and Hispanics receiving the lowest scores (Chernoff, Flanagan, McPhee, &

Park, 2007). An assessment of expressive language skills revealed the same general trend, but differences

associated race and ethnicity were smaller.

Parenting and home environments. Of course demographic variables such as income and parental

education are simply indicators of factors that condition the kinds of interactions that occur between

parents and children. Not surprisingly, the nature of adult-child interactions in the home is predictive of

children’s language growth. The NICHD Child Care Study videotaped mother-child interactions in the

home, scored them for maternal sensitivity and responsiveness, and after controlling for a large set of

demographic variables, found moderate effects on measures of language and cognitive development at 36

and 54 months (NICHD Early Child Care Research Network, 2006). This finding is consistent with

studies that have examined the quality of support for literacy in the home and found strong evidence that

practices such as ownership of books, regular book reading and library use account for significant

variability in early language and literacy development (Dickinson & Tabors, 2001; Roberts, Jurgens, &

Burchinal, 2005; Whitehurst & Lonigan, 1998).

Careful examinations of the details of mother-child interaction have identified specific variables

that directly relate to more rapid language learning. One study found that language learning of 9 and 13

month old children is more rapid when parents are responsive (Tamis-LeMonda, Bornstein, & Baumwell,

2001). Similarly, another study of children at 6, 12, 24, and 40 months found faster rates of cognitive

development when mothers were sensitive to children’s focus of attention and interests (Landry, Smith,

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Miller Loncar, & Swank, 1997). Vocabulary growth is related to how much language children hear (Hart

& Risley, 1995; Walker, et al., 1994), especially when this input includes many varied words (Hoff &

Naigles, 2002; Huttenlocher, Vasilyeva, Cymerman, & Levine, 2002; Pan, Rowe, Singer, & Snow, 2005).

Children also acquire words faster when adults provide semantically contingent responses – comments

that respond to what a child says or intends (Cross, 1984; Landry, Smith, & Swank, 2006a; Nelson, 1989;

Snow, 1983) and parents provide useful information about the meaning of words (Tabors, Roach, &

Snow, 2001; Weizman & Snow, 2001). Children benefit when parents engage them in sustained talk

about a single topic, including telling stories about past experiences (Bishop & Adams, 1990; McCabe &

Peterson, 1991; Peterson, Jesso, & McCabe, 1999b).

The type of interactions that foster language learning are likely to occur most often when parents

and children are engaged in a shared activity that is conducive to sustained talk. Meals are one such time

and variation in vocabulary used during meals relates to children’s later vocabulary size (Weizman &

Snow, 2001). Many studies have been conducted examining the impact of book reading and these have

consistently found that variation in how often preschool children hear books read is related to later

language growth, accounting for around 8% of the variance in vocabulary growth (Bus, van Ijzendoorn,

& Pellegrini, 1995; Mol, Bus, de Jong, & Smeets, 2008; Scarborough & Dobrich, 1994; Schwegler &

Lipp, 1983), but that direct effect most likely underestimates the true impact of book reading because it

fails to take into account indirect effects that occur when enhanced vocabulary supports phonemic

awareness and decoding (Sénéchal, Ouellette, & Rodney, 2006). It may be because of these indirect

effects that storybook exposure in kindergarten predicts language and reading comprehension through

grade 4 (Sénéchal & LeFevre, 2002; Sénéchal, LeFevre, Thomas, & Daley, 1998; Sénéchal, et al., 2006).

Given that regular book reading consistently has been found to be associated with stronger early

language growth, the finding of substantial differences in how often parents report reading to their

children is sobering. Whereas in 2005 92% of White parents reported regular reading, only 72% of

Hispanic and 78% of African-American parents said they read to children three or more times a week. It

is encouraging that both of these groups showed about a 15% increase in reported reading since 1993,

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when the same national survey was administered. These group differences correlate with the educational

background of parents, because in 2005 60% mothers with less than a high school education reported

regular reading compared with 75% of those who graduated from high school and 90% with BA degrees

(National Center for Education Statistics, 2008). These differences appear to reflect specific differences in

the behaviors parents emphasize because demographic distinctions did not relate strongly to how often

adults told stories to children or taught letters or words. Indeed, African-American parents reported more

frequent teaching of letters and words than did White families.

Bilingual children. Children who are learning English as an additional language have the

opportunity to master two languages, but this can come at a price if children do not acquire the language

skills required for success in the language of the school they attend. Paez and colleagues (Páez, Tabors, &

Lopez, 2007) studied dual language learning children from the beginning to end of preschool when they

were four years old, tracking bilingual children in the United States and monolingual Spanish speakers in

Puerto Rico. At entry to preschool the vocabulary scores in both languages for both groups were nearly

two standard deviations below the mean and sentence recall ability was somewhat stronger across

languages for all children. Dual language learning children made steady growth relative to national norms

on the English language assessments from the beginning of preschool to the end of first grade, with

vocabulary gains of about ½ a standard deviation in vocabulary and sentence recall (Páez & Rinaldi,

2006). Over this same time frame dual language learners lost a full standard deviation relative to national

norms in Spanish vocabulary while retaining sentence recall and narrative skills (Uccelli & Páez, 2007).

During preschool year monolingual Spanish speakers displayed small gains on both tasks (Páez, Tabors,

& López, 2007).

Hammer followed children through two years of Head Start and continued to the end of

kindergarten (Hammer, Lawrence, & Miccio, 2007). Of these children 53 heard English at home (home

English exposure – HEC) and 35 were exposed to it in school (SEC). Both groups showed strong growth

trajectories, with some reduction in the differences in English vocabulary (Hammer, Lawrence, & Miccio,

2008). SEC children had stronger Spanish than HEC children and both groups showed strong growth

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trajectories with some increase in the gap between the groups in Spanish vocabulary knowledge

(Hammer, et al., 2008) but not the dramatic decline noted by Páez and Rinaldi (Páez, et al., 2007).

At the end of kindergarten Hammer assessed children’s print-related knowledge and found that

the rate of growth in English during Head Start predicted all kindergarten outcomes for both groups and

that growth in Spanish predicted all outcomes except Spanish letter knowledge. Assessments of language

status at a single point in time were not good predictors of kindergarten literacy (Hammer, et al., 2007).

Páez and Rinaldi (2006) also found that both English and Spanish vocabulary knowledge predicted

English word reading at the end of first grade. Surprisingly, when English vocabulary was entered after a

measure of phonological awareness in a stepwise regression model, phonological awareness was no

longer significant.

In sum, when children from low-income homes where Spanish is spoken attend preschool

classrooms where the language of instruction is English, they make steady growth in English and lose

Spanish vocabulary, but retain sentence-level and discourse skills. Growth in vocabulary knowledge in

both languages is associated with stronger decoding and print knowledge at the end of kindergarten and

grade one.

Childcare and preschool classrooms. Many young children spend considerable time in child care

and preschool classrooms and variability in the quality of those settings has an impact on children’s

language development that can be traced into the early elementary grades (Peisner Feinberg & Burchinal,

1997; Peisner Feinberg, et al., 2001). The largest study conducted, the NICHD Study of Early Child Care

found that after controlling for a large number of demographic, child and parenting variables, the quality

of teacher-child interaction is predictive of language and cognitive development at the end of preschool

(NICHD Early Child Care Research Network, 2000, 2002), with causal evidence that child care and

preschool classrooms affect subsequent academic outcomes (NICHD Early Child Care Research

Network & Duncan, 2003).

Variability in specific features of preschool classrooms has been linked to language development.

Fall-spring growth in comprehension of complex syntactic forms among children from low-income

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homes is affected by the complexity of teacher’s syntax input (Huttenlocher, et al., 2002), a correlational

finding that has been bolstered by experimental findings (Vasilyeva, Huttenlocher, & Waterfall, 2006).

Vocabulary growth has been found to be affected by the quality of story reading in preschool classrooms,

with analytic conversations being predictive of end-of-kindergarten vocabulary scores (Dickinson, 2001a;

Dickinson & Porche, under review; Dickinson & Smith, 1994). Group discussions that include more talk

that is conceptual in nature also has been linked to stronger language skills (McCartney, 1984).

Vocabulary growth also has been related to conversations that occur during meal times and free play

(Dickinson, 2001b; Dickinson & McCabe, 2001). In particular, children benefit when teachers are

responsive to children and do not dominate interactions, when they use more sophisticated vocabulary,

and when they encourage children to extend and clarify their thinking. Dickinson and Porche (under

review) recently found evidence of moderate indirect effects of such experiences when children were four

years old on end-of-fourth grade assessments of reading comprehension, decoding, and vocabulary. This

finding reveals greater lasting effects of preschool experiences than have been found previously, possibly

because the analyses examined very specific features of teacher-child interaction and because analyses

examined indirect associations. Also interesting is the fact that relatively small differences in overall input

have been found to be predictive of children’s learning. Connor and colleagues (Connor, Morrison, &

Slominski, 2006) videotaped 2 hours of classroom interaction in 34 classrooms and found that on average

only 4 minutes was spent reading books, and one minute divided among vocabulary, comprehension,

concepts of print and “other” language activities. Nonetheless, differences among classrooms were

associated with children’s vocabulary and code-related skills.

Summary

It is widely acknowledged that language ability is critical for skilled reading and that there is

continuity in language ability between the preschool and the middle elementary school years. The rate at

which young children acquire language in the years before they enter school lays the groundwork for

long-term reading success. Unfortunately, there are persistent and large disparities in young children’s

language skills associated with academic success that are closely linked to SES, race, ethnicity, and home

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language, a set of highly related demographic variables; vocabulary is an area of special vulnerability.

Variability in language and reading appear to be primarily controlled by environmental factors, and

studies of the earliest phases of language acquisition indicate that language processing mechanisms are

emerging in response to language exposure even as children are just beginning to comprehend and

produce language. Thus, environmental factors strongly condition children’s linguistic abilities as they

enter school and variability in children’s linguistic knowledge and language processing strategies affect

the rate at which they learn language.

This spiral of success in which later learning builds on earlier accomplishments is most evident

with respect to vocabulary learning. In group instructional contexts in which book reading is used to

foster learning, preschool children with stronger vocabularies typically learn more new words than their

peers who have smaller vocabularies (Penno, et al., 2002). Also, children with stronger vocabularies

learn vocabulary from interacting with peers with larger vocabularies whereas children with the most to

gain, those with small vocabularies, tend not to reap the benefits of interacting with more verbal peers

(Mashburn, Justice, Downer, & Pianta, 2009). These findings suggest that children with stronger

language skills are more adept at quickly picking up new words from incidental exposure, the process that

drives most language learning. If society is to address seriously the disparities in educational success that

correlate with income, education, race and ethnicity then early and sustained interventions designed to

build language skill are necessary. But can we fashion effective interventions for children who need

added support? Policy makers and researchers have sought to create such settings for decades, but with

varying degrees of success. We now turn to a review of those efforts.

Intervention Efforts

A multitude of approaches to enhancing the language development of young children have been

devised and tested, with these being provided in homes and classrooms. Interventions vary greatly in the

age of the target child, and the scale, scope, and mechanisms for delivering interventions. While most

studies have targeted three- and four-year olds some have targeted younger children, with these early

interventions primarily seeking to change parenting practices. Some efforts have a very narrow scope in

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that they target specific language-related skills, are delivered in a relatively limited period of time, and

often include relatively well specified strategies. Dialogic reading, a widely adopted means of reading

books, is an example of an intervention with a narrow scope. Other interventions such as comprehensive

curricula have a broad scope. Such approaches span much more time and vary in the degree to which they

specify teaching behaviors. Intervention scale varies from small scale experimental studies that are

carefully supervised by researchers or program originators to large scale efforts such as Head Start. By

intervention mechanism we refer to the process by which the intervention is delivered. Interventions

often seek to change specific dimensions of how teachers or parents interact with children, but the route

to effecting changes varies from direct and intensive coaching that may include use of videotaping, to

curricular interventions in which teachers are supported in use of a particular program, to educationally-

based professional development efforts designed to deepen teachers’ understanding of a domain and

shape their attitudes about what constitutes appropriate practice. These aspects of interventions co-vary;

for example, large-scale efforts (e.g., state funded prekindergarten) have a broad scope because programs

must address all of children’s needs and they primarily target four year olds. Nonetheless these

dimensions are of analytical value as they provide a means to gain clarity about promising approaches.

First we will review efforts that serve children from birth – three and then those that are for three-

and four-year old children. As we consider approaches for older children we will first discuss approaches

that employ book reading and then examine other strategies. Variety in the mechanisms for delivering

interventions will be integrated into each section. Approaches to supporting children who speak a

language other than English at home will be considered separately. We will end with tentative

conclusions about promising approaches and recommendations for future efforts.

Birth - Three

Parent-Focused Interventions

There is a long tradition of providing services to infants and toddlers, with home visitor programs

becoming popular since the 1980’s. These have taken many forms, but a common distinguishing element

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is the delivery mechanism of providing intervention services by having a person go to the home. Many

such programs provide broad-based consultation and support while others use focused coaching to teach

parents how to interact with their children. Since the mid-1990’s center-based child care has grown in

popularity with increases in federal funding for Early Head Start. These center-based models often use a

mixed model that combines home visitors and center-based care, either at the same time or sequentially

(e.g., home visitors for 12 months then center care).

Many home visitor programs seek to educate and support parents in order to reduce maltreatment,

foster positive relationships, and link families to services. Although language is a focus of some, it

usually is secondary to the emotional climate and nurturing qualities of mother-child interactions. We

mention these programs because responsive parenting is a cornerstone of strong attachment and is vital to

fostering early language. Also, public dollars are limited and were there to be a push to increase funding

for language-oriented interventions this might have to come from a reduction in support provided for

other types of programs. Two meta analyses of home visitation programs have come to somewhat

different conclusions regarding their efficacy. A review of 40 programs that seek to reduce maltreatment

found evidence of moderate effects on prevention of abuse (.26) and family functioning (.23 to .38)

(Geearaert, 2004). But a meta-analysis that included 60 home visitation programs found weaker evidence

for these same outcomes (Sweet & Appelbaum, 2004) and small effects on cognitive (ES = .184) and

socioemotional (ES = .096) outcomes. They concluded that, although there is evidence of program

effects, it is uncertain that the size of the effects is sufficient to warrant the amount of money currently

being spent on these programs.

Rigorous evaluations of several of the most widely adopted parent support programs failed to find

evidence of positive effects. An evaluation of Parents as Teachers, a program now in 49 of 50 states,

looked for effects on mothers’ knowledge of development, their sense of competence as parents, the

quality of home learning environment, children’s cognitive and language skills and social and physical

development and found limited evidence of effects (Wagner, Spiker, & Linn, 2002; Wagner & Clayton,

1999). That said, certain subgroups did show some positive effects: parents with the lowest incomes,

17

Latina mothers, and those who received the most intense services. Evaluations of three other widely

implemented home visiting programs, Hawaii Healthy Families (Duggan, et al., 1999), Healthy Families

America (Daro & Harding, 1999). Healthy Families Alaska (Duggan, et al., 2007), failed to find changes

in mother-child interaction, or child health or development. In contrast, the Nurse Home Visiting

Program has been found to have positive effects on maternal life experiences (e.g., time between

pregnancies, family size), child attendance at group child care, receptive vocabulary, and reported

behavior problems (Olds, et al., 1999; Olds & Kitzman, 1993; Olds, et al., 2004). This program may be

especially effective because it begins before birth and continues for up to 71 additional visits, and it uses

trained nurses who followed carefully detailed guidance for each visit.

Interventions that focus on language or that coach parents of infants and toddlers in behaviors that

enhance relationship quality and language, have been found to have significant effects. In its review of

language-focused intervention programs, the NELP reviewed 23 parent-focused programs, 18 of which

had measures of language learning. It found a modest sized effect on vocabulary (.41) and a modest

effect on broader language measures (.27). Programs for parents of children birth – three were found to

be somewhat more effective than those targeting parents of older children (.42 vs. .32). The Panel also

identified a set of programs that had highly focused language enhancement goals, four of which, for

infants and toddlers and found these had large effects (1.07), double the effect size of language-focused

programs for children three- to five-year olds (National Early Literacy Panel, 2009a). These meta

analytic results suggest that programs designed to help parents foster their children’s language can have

strong effects when they are highly focused on fostering early language.

Two programs found to have effects on parenting and child outcomes help parents in becoming

more responsive by videotaping them as they interact with their infants and toddlers and using these tapes

to coach parents in how to more effectively engage their child. Playing and Learning Strategies (PALS;

Landry, et al., 2006a) was found to improve parenting sensitivity and child language. The Verbal

Interaction Project (VIP; Levenstein, Levenstein, & Oliver, 2002), also was found to enhance parenting

and child language. The Parent-Child Home Program (PCHP) serves mothers of two- to three-year olds

18

(Parent-Child Home Program, 2007). Home visitors meet with mothers, the mother is shown how to use a

new toy in an educationally enriching manner, practices while the visitor observes and then is given the

toy to continue playing with the child. Home visitors are trained and are guided by a prescribed

curriculum. A common feature of programs found to be effective in changing parenting and fostering

language growth is that they are targeted on changing specific behaviors that are linked to enhanced

language development and home visitors are guided by a well-prescribed curriculum.

A different, less coaching-intensive approach has been found to work with mothers of three- to

four-year olds in which mothers were encouraged to engage their children in conversations about the

past, through open-ended questioning, feedback, and following the child’s lead. Significant

improvements were noted in receptive vocabulary and the use of decontextualized language in narratives

(Peterson, Jesso, & McCabe, 1999a). Encouraging parents to talk elaboratively about past events, or

reminisce, also has been found to have a positive effect on children’s memories and use of narrative

devices (Reese & Newcombe, 2007).

Center-based Care

Center-based care also has been found to have beneficial effects on children in the birth-three age

range. The Abecedarian project began providing high quality child care to a randomly selected group of

infants and continued to do so until children were age five. Positive effects have been reported for

cognitive and academic tests from age 3 to 21 (Campbell, Pungello, Miller Johnson, Burchinal, & Ramey,

2001). Analyses of examined growth patterns revealed large effects on IQ (d = .74) while children were

in the child care settings followed by a slow steady decline in effect size to age 15, when modest effects

of the birth – five intervention were still detected on IQ (d = .37). A partial replication study again found

benefits associated with center-based care (Wasik, Ramey, Bryant, & Sparling, 1990). Similarly the

Infant Health and Development Program (IHDP) provided center-based care and parental support to

children, most of whom were from low-income homes, between birth and age three children. Effects also

were seen at age eight (Hill, Brooks Gunn, & Waldfogel, 2003), with some children still showing benefits

at age 18 (McCormick, et al., 2006).

19

While the Abecedarian and IHDP projects were small scale research and demonstration efforts,

Early Head Start is a large scale federally funded program for low-income families. An evaluation of the

effectiveness of 17 programs found evidence of positive effects at age three on measures of cognition,

receptive vocabulary, parental ratings of behavior, and engagement and sustained attention when in a

semi-structured play tasks with their parents (Love, et al., 2005). However, the differences between

groups were quite small on standardized assessments of vocabulary (2.1 points, effect size of .13) and

cognition (1.6 points, effect size of .12). The strongest effects were found for programs that provided

both home- and center-based care. A study of the 11 programs that only delivered services through home-

based methods found that benefits were associated with the percentage of time during the visits spent

dealing with issues related to the child rather than rapport building or general family issues (Raikes, et al.,

2006).

The birth – three years lay the groundwork for subsequent language learning and provide a fertile

opportunity for interventions to have a positive impact on language learning. High quality center-based

care, and parent-focused interventions that target language and foster responsiveness have been found to

have significant lasting effects on language and other outcomes. The most common interventions for

infants and toddlers – those that employ parent support, education and consulting – often have not been

found to have measurable effects.

The Preschool Years

Different approaches have been taken to address the language learning needs of preschool

children, ranging from large-scale efforts with a broad scope such as provision of preschool to narrowly-

focused experimental programs.

Large-Scale Approaches

The need for educational support for children from low-income homes long has been recognized

and was first addressed on a national scale with the establishment of Head Start. The effects of Head

Start have been described by longitudinal observational studies that have tracked successive waves of

children. The Family and Child Experiences Survey (FACES) followed a group of children beginning in

20

2000 and found they gained 3.8 standards points in receptive vocabulary (effect size = .26) with the

greatest gains being seen among children who started in the bottom quartile and those in the program for

two years. Children who started in the top quartile lost ground (Zill & Resnick, 2006). Results reported

for children in the 2003 cohort revealed relatively large fall-spring vocabulary gains for Hispanic children

(4.9 standard score points) and small gains for White non-Hispanic (2.3 points) and African-American

children (2.1 points) (Zill, Sorongon, Kim, Clark, & Wolverton, 2006). Additionally, Spanish-speaking

children showed significant gains in English vocabulary without a decline in Spanish vocabulary.

Comprehensive curricula, higher teacher salaries, and parent involvement were associated with

vocabulary gains, but measures of classroom quality did not predict growth. An effectiveness study that

compared eligible, at-risk students randomly assigned to Head Start with a comparable group of students

not assigned (Administration for Children & Families, 2005) found a small effect on receptive vocabulary

(d = 0.12) and color naming (d = 0.10) for three-year olds enrolled in Head Start compared to the control

group. There were no other significant effects on language-related outcomes for three-year-olds and no

effects on language for four-year-old children. There were, however, modest effects on children’s

knowledge of letters.

Efforts to support language growth among preschool-aged children using curriculum-based or

programmatic intervention have had difficulty demonstrating effects on language. The National Early

Literacy Panel (2008) found no significant difference on children’s oral language outcomes between

programs that implemented a literacy-focused curriculum and those that did not. A meta-analysis of the

effects of preschool curriculum interventions on vocabulary outcomes yielded no significant effects

overall (Darrow, 2009). These two meta-analyses included many studies done as part of the Preschool

Curriculum Evaluation Research Study (PCERS) that examined 14 curricula (Preschool Curriculum

Evaluation Research Consortium, 2008), 11 of which claimed to have an explicit focus on oral language.

On the two language outcomes examined, receptive vocabulary and grammatical understanding, only one

curriculum yielded positive effects at the end of preschool, and one additional curriculum positively

impacted language outcomes at the end of kindergarten. In a separate report one of these curricula

21

showed positive effects on language comprehension and expressive vocabulary (Assel, Landry, Swank, &

Gunnewig, 2007), indicating the need to measure various facets of language when determining

curriculum effects.

State-funded, public pre-kindergarten programs have rapidly gained popularity in recent years,

with most of these serving at-risk populations. A correlational study of the pre-k programs in 11 states

included nearly 3,000 children (Howes, et al., 2008). The researchers found a small effect on receptive

vocabulary and expressive language and, in contrast to prior studies, determined that indicators of

classroom processes are predictive of language gains whereas structural indicators such as teacher

education and teacher-child ratio are not. A study of pre-k programs in five states that employed a

regression continuity design found that public preschool significantly increased children’s receptive

vocabulary (d = 0.26), equating to three months more growth than otherwise expected (Barnett, Lamy, &

Jung, 2005). Finally, an evaluation was conducted of New Jersey pre-kindergarten programs instituted in

response to a court order that required the state to establish high-quality programs with bachelor’s-level

certified teachers. Regression discontinuity was combined with a longitudinal cross-sectional design that

compared children who did and did not attend the Abbott pre-K program (Frede, Jung, Barnett, Esposito,

& Figueras, 2007). Both designs found evidence of effects on receptive vocabulary of about four standard

points for one year of attendance and about seven points for two years of attendance – an impressive

boost of nearly ½ of a standard deviation.

The Chicago Parent-Child program is another large-scale program that has been studied using

quasi-experimental designs. It has been found to have effects on high school graduation, with the effects

being mediated by a variety of school, family and child variables (Reynolds, Ou, & Topitzes, 2004). A

recent observational study of this program examined fall-spring gains among a sample of the classrooms,

roughly half of which are funded by Head Start, and found growth of 4.8 standard scores (effect size

= .24) in receptive vocabulary knowledge (PPVT-4). The gains were smallest among children from

English-speaking homes (2.9 points, ES = .19), and larger among children from homes where other

languages are spoken (5 points, ES = .47) (Ross, Moiduddin, Megher, & Carlson, 2008).

22

Finally, Early Reading First (ERF) is a recent federal effort to improve language and literacy

outcomes for at-risk children. Programs receive grants to create high-quality programs by providing

professional development and intensive coaching and using preschool curricula that target language and

literacy. A national evaluation of the program that employed a regression discontinuity design found a

positive impact on classroom practices and children’s print and letter knowledge, but not on oral language

(expressive vocabulary and auditory comprehension) or phonological awareness (Jackson, 2007).

However, more promising results came from a study that combined results from eight programs involving

nearly 100 teachers and 3,000 children (Ashe, Reed, Dickinson, & Wilson, 2009; Wilson, Morse, &

Dickinson, 2008) that all used the same curriculum, Opening the World of Learning (Schickedanz &

Dickinson, 2005). Data collected by different research teams were pooled and subjected to a secondary

analysis. Control groups are not present in these ERF studies. Evidence of effectiveness came from

growth relative to national norms and year-to-year improvements of children attending the same program

because year-to-year gains indicate within-program improvements. Gain scores demonstrated a steady

improvement as the program continued to be implemented over time: average receptive vocabulary

growth was 2.6 points in year one, 5.5 points in year two, and 6.6 points in year three. Sizable gains were

also found on other measures of language.

Thus, studies of large-scale programmatic interventions reveal that program impacts on language

vary, with evaluations of the largest scale efforts (Head Start, 11 state pre-kindergarten) finding either no

effects or small effects while other evaluations find gains approaching half of a standard deviation.

Studies that found stronger effects tended to have higher funding levels that make available coaching and

professional development and include teachers with BA-level training. Some are newer programs

fashioned when there has been heightened awareness of the need to boost student outcomes. These

programmatic interventions are broad in scope because they encompass the entire classroom day;

therefore they include many different activities and encourage teachers to employ many different

instructional strategies. A challenge facing large-scale interventions is the fact that the curricula in use

may not have been developed with a particular focus on fostering language outcomes. Also, published

23

curricula tend to poorly specify what high fidelity implementation of the curriculum entails (Preschool

Curriculum Evaluation Research Consortium, 2008). Guidance regarding methods that should be used

can come from focused interventions that identify promising practices and teaching behaviors. We now

turn to consider the most common such approach, book reading.

Shared Book Reading

By far the most common early childhood interventions targeting language involve shared book

reading. These interventions have also yielded the most consistent, positive effects on oral language

skills in meta-analysis, with an average effect size of 0.73 (National Early Literacy Panel, 2008). Parents

often deliver book-reading interventions, with many efforts including parent training designed to

encourage teachers to use particular book-reading strategies.

Parent-focused. A meta-analysis of parent-preschooler reading yielded an effect size for frequent reading

of 0.67 on language skills (Bus, et al., 1995). The most commonly employed reading-based intervention

is Dialogic Reading, a method of interactive book reading the involves using strategies such as

questioning techniques and feedback, typically delivered one-on-one or in small groups (Whitehurst, et

al., 1988). In an examination of dialogic reading interventions implemented exclusively by parents (Mol,

et al., 2008), the method resulted in significant effects on child language outcomes, including average

effects on expressive (d = 0.59) and receptive (d = 0.22) vocabulary as compared to typical shared

reading. This effect was much smaller in older preschoolers (age four to five) and with children at risk

for language impairments. Across a number of experimental studies conducted with a variety of ethnic

and socioeconomic groups, this approach most consistently has an impact on expressive language, it

produces mixed results on verbal expression and rarely affects receptive language, though it may support

narrative skill, (Hargrave & Senechal, 2000; Lonigan & Whitehurst, 1998; Valdez-Menchaca &

Whitehurst, 1992; Whitehurst, et al., 1994a; Whitehurst, et al., 1994b; Zevenbergen, Whitehurst, &

Zevenbergen, 2003). Training parents in Dialogic Reading methods was beneficial as compared to

general conversational techniques, leading to higher rates of child response as well as modest

improvements in the number of different words used and in mean length of utterances (MLU; Dale,

24

Crain-Thoreson, Notari-Syverson, & Cole, 1996). Several studies also showed moderating effects for

compliance, indicating that the program must be well-implemented to produce optimal effects.

Community-based efforts at improving child language through family book reading have had

some success. Reach Out and Read is a pediatric clinic-based program that encourages parent-child book

reading by having a doctor “prescribe” book reading at well child visits. When fully implemented,

parents also get coaching in book reading while in the waiting room. This method was found successful

across several studies (Needlman, Klass, & Zuckerman, 2006). For example, in one study African

American and Latino low-income preschool children showed significant increases in receptive and

expressive language in both English and Spanish as a result of the program (Mendelsohn, et al., 2001). A

similar program disseminated through the public library where parents were trained in Dialogic Reading

techniques significantly improved children’s verbal expression but not vocabulary skills (Huebner, 2000).

Notably, each of these community-based interventions provided parents with storybooks to read at home.

Center-based delivery. Interventions employing interactive reading techniques yield a larger

effect on oral language when implemented in schools than when delivered by parents at home, as

demonstrated by a synthesis of such interventions (Mol, Bus, & de Jong, 2009). Mol and colleagues

report that these interventions had an average effect of 0.62 on expressive language and 0.45 on receptive

language as compared to control conditions which had either no book reading or reading without

interactive techniques. This finding may be partially attributed to interventions delivered by researchers,

as well as the increased control and compliance monitoring that may take place when interventions are

delivered in schools and centers. An indication of the importance of high fidelity implementation is the

fact that interventions delivered by an experimenter, particularly those delivered one-on-one, were more

effective than those delivered by teachers in a natural setting.

Dialogic Reading has garnered the most attention and has been exported from its original use in

homes to group settings in classrooms, but such uses of the method, especially when employed with older

preschool children, have been found be of only limited effectiveness. In fact Dialogic Reading has been

found to be less effective than other interactive shared reading interventions that have demonstrated clear

25

success at supporting language development (Mol, et al., 2009). One example of an effective classroom-

based intervention is Story Telling and Retelling, a preschool program affiliated with Success For All that

emphasizes retelling of shared stories, significantly increased performance on measures of vocabulary,

sentence imitation (syntax), and oral comprehension (Karweit, 1989).

Studies of book reading have identified specific techniques that are effective at building language

in preschool children. Observational data reveal benefits of analytic conversations about story events and

the meanings of words that have been traced from preschool to the end of kindergarten and grade four

(Dickinson & Porche, under review; Dickinson & Smith, 1994). Repeated reading of books with special

attention to explaining the meanings of words also has been found to increase word learning when

compared to single readings and/or reading without attending to vocabulary (Biemiller, 2006; Sénéchal,

1997). These strategies were also successful at improving the English vocabulary acquisition of ELL

children regardless of their second language level (Collins, 2005). Asking questions about target words

while reading was shown to improve children’s comprehension and production of those words, and

scaffolding questions from low- to high-demand facilitated deeper understanding of word meanings

(Blewitt, Rump, Shealy, & Cook, 2009). The identification of such strategies has been important because

it provides guidance to professional development interventions.

Interventions Targeting Specific Language Skills

A number of interventions have been developed with the intention of supporting specific

language abilities. We discuss these as a distinct cluster because they tend to be narrow in scale and

scope.

Phonological awareness. Phonological awareness training programs are typically associated with

print-related outcomes, but phonological skills are a key component of literacy success and, as we noted

above, are in part an outgrowth of early language development. A meta-analysis of phonological training

interventions (Bus & van Ijzendoorn, 1999) indicates that on average these programs had significant,

positive effects on phonological awareness (d = 0.73) and early reading (d = 0.70). These effects were

significantly greater when the interventions took place in preschool as compared to elementary grades,

26

demonstrating the importance of early training in phonological skills. Although phonological awareness is

partly conditioned by lexical development, interventions that foster phonological awareness have limited

effect on other language skills. The most common intervention examined, Sound Foundations (Byrne &

Fielding-Barnsley, 1991b), consistently increased phonological awareness, but studies have not reported

effects on broader language skills (Byrne & Fielding-Barnsley, 1991a). When paired with Dialogic

Reading, Sound Foundations did not change the pattern of vocabulary results (Whitehurst, et al., 1994b;

Whitehurst, et al., 1999). A program that employed phonological games and exercises focused on skills

such as rhyming and syllabication impacted these specific phonological skills but not vocabulary or

language comprehension (Lundberg, Frost, & Petersen, 1988). Also, the use of computer-assisted

instruction for phonological training of at-risk students was successful at increasing the phonological

skills of rhyming and elision, but there were no differences between treatment and control groups on oral

language outcomes (Lonigan, et al., 2003).

Syntax. While relatively few studies have focused on developing the syntax of preschool-aged

children, the research indicates syntactic interventions can be highly effective. Focused stimulation or

modeling highlighting particular grammatical forms with language-delayed preschoolers led to significant

gains in grammatical expression, and was effective whether delivered by a speech-language pathologist or

a parent (Fey, Cleave, Long, & Hughes, 1993). An intervention which compared the effects of reading

books with different sentence structures found passive sentence input increased production of passive

sentences with fewer errors and greater comprehension as compared to active sentence input (Vasilyeva,

et al., 2006). Other experiments have used similar syntactic priming tasks for transitive and dative

sentence structures with young children to demonstrate how exposure can impact production of even

abstract grammatical forms (Savage, Lieven, Theakston, & Tomasello, 2003; Shimpi, Gamez,

Huttenlocher, & Vasilyeva, 2007). A brief, focused intervention teaching questioning patterns to two- to

three-year olds effectively increased their use and syntactic generalization, demonstrating the speed and

ease of syntactic training in young children (Valian & Casey, 2003). These findings suggest syntax is an

aspect of language that is responsive to targeted input interventions.

27

Professional Development

Professional development is an important component of many efforts to enhance children’s

learning in centers. One approach that has been found successful is to deliver professional development

through lectures, demonstrations and workshops with some limited on-site coaching (Dickinson &

Caswell, 2007). Technology is now being employed in efforts to deliver professional development. In one

effort videoconferencing was used to deliver the lecture-discussion content of a course-based intervention

and this resulted in improved classroom practices and student outcomes (Dickinson & Brady, 2005). A

somewhat similar model was Heads Up! Reading. It combined satellite delivery of content with site-

based coursework done as part of a credit-bearing course (Jackson, et al., 2006) and was found to have

some impact on classroom practices and children’s literacy skills. Similarly, a model that combined an

online course in supporting language and literacy development with in-class mentoring and detailed

feedback on student progress yielded the most positive effects on teacher practice and children’s skills as

compared to use of only the individual components; detailed feedback to teachers had significant effects

on children’s expressive vocabulary (Landry, Anthony, Swank, & Monseque-Bailey, 2009). Another

model combined professional development with coaching that was provided by coaches who reviewed

videotapes of teaching and supplied teachers written feedback linked to the videotaped lessons (Pianta,

Mashburn, Downer, Hamre, & Justice, 2008). This approach led to increased teacher use of research-

based language support strategies. These types of interventions are promising for delivering professional

development on a large scale or in remote or rural locations.

Projects with professional development and coaching delivered by investigators with high levels

of fidelity have been found to have measurable effects. Wasik and Bond (2001) used an experimental

design approach to study the effectiveness of an intervention that trained teachers to employ interactive

book reading methods that included an emphasis on vocabulary. It resulted in significant positive effects

on both expressive and receptive vocabulary. In a follow-up study in Head Start, with similar techniques

and more intensive professional development that included in-class coaching, the effects on expressive

vocabulary (0.44) and receptive (0.73) were statistically and practically significant (Wasik, Bond, &

28

Hindman, 2006). Two other large-scale studies that included professional development and systematic

feedback to teachers about their performance were found to have beneficial effects (Landry, Swank,

Smith, Assel, & Gunnewig, 2006b; Pianta, 2006). Finally, an experimental study of the effectiveness of

training day care staff in language facilitation methods combined with ongoing support found increases in

children’s language use in peer-directed talk, number of utterances, and multi-word combinations

(Girolametto, Weitzman, & Greenberg, 2003). These studies highlight the value of coaching or providing

feedback to teachers regarding their performance.

Language gains also may be realized by interventions that seek to improve the social and

emotional climate of classrooms in addition to opportunities for language learning. Evidence for this

comes from an approach delivered in Head Start centers. Teachers were provided a well-specified

curriculum and received a year of coaching. Results of a randomized control trials study revealed a small

but significant impact on expressive vocabulary (effect size = .15), but not on sentence imitation or

grammatical understanding (Bierman, et al., 2008). Moderate effects were seen on measures of

phonological awareness.

Interventions Targeting Bilingual Children

Although many of the intervention studies outlined here included some child participants who

were English Language Learners (ELL), certain interventions are specifically designed to enhance the

language development of young bilingual children. These interventions are typically evaluated for their

facility in building second language skills (L2) in English while also building or maintaining native

language (L1) abilities.

A number of studies have evaluated types of bilingual programs in preschools. Two studies

found that the High/Scope curriculum delivered in Spanish and English significantly affected bilingual

children’s reception, production, and verbal complexity in English, and had no negative effects on L1

language, as compared to no preschool (Rodrìguez, Dìaz, Duran, & Espinosa, 1995; Winsler, Dìaz,

Espinosa, & Rodriguez, 1999). A study that compared two-way immersion in English and Spanish with

English-only preschool formats, both also with the High/Scope curriculum, found significant effects on

29

English language skills for both groups, but on Spanish vocabulary only for the two-way-immersion

group (Barnett, et al., 2005). Finally, researchers evaluated the effects of a comprehensive literacy-

focused preschool curriculum in English-only and in Spanish transitioning to English for ELL

preschoolers (Farver, Lonigan, & Eppe, 2009). This curriculum yielded significant growth in language

and literacy skills for both groups in English, with the transitional group outperforming the English-only

group in definitional vocabulary and print knowledge. Only the transitional group demonstrated

significant growth in Spanish language skills. These studies suggest that for preschool-aged ELL

children, bilingual curricula are most effective at building English language proficiency while

maintaining native language skills.

Additionally, multimedia-supported reading instruction improved vocabulary for ELL children

(Verhallen, Bus, & de Jong, 2006), and multimedia-enhanced instruction of science content in early

childhood classrooms improved targeted word learning for ELLs, closing the gap with native English

speakers on this measure and narrowing the gap on overall receptive vocabulary (Silverman & Hines,

2009). These findings begin to build evidence of promising language interventions for bilingual children.

Summary of Intervention Studies

Effective interventions have been delivered using different mechanisms, but effects are most

consistently seen for those that have a narrow scope and are small in scale. Interventions with consistent

evidence of effectively fostering language are: (a) interventions with parents designed to foster language

and parenting sensitivity, (b) shared book reading whether delivered by parents or in centers, especially

when it includes repeated reading, attention to vocabulary, and supportive discussion, (c) Dialogic

Reading when used with children aged two to three, (d) interventions focused on improving phonological

skills and syntax, particularly for children at risk for difficulties in these aspects of language, (e)

professional development, especially when it incorporates coaching and feedback, and (f) bilingual

preschool programs. Center-based care tends to have beneficial effects, but large-scale interventions have

shown only mixed success in enhancing language learning. Those that are successful specifically attend

30

to language and have funding to hire highly qualified teachers and provide professional development and

coaching.

The most pressing need is to identify approaches that can be used on a large scale. It is now

apparent that effectiveness requires professional development and some form of coaching, but for

changes to be maintained there may need to be strategies to ensure that teachers adopt and sustain key

practices with a reasonable degree of fidelity. We raise this issue because improvements in observed

practices may not translate into better child outcomes, as evidenced by the national evaluation of Early

Reading First that found substantial improvements in teaching practices but no significant changes in

children’s language outcomes (Jackson, 2007). We have very little knowledge about exactly how much

change in particular aspects of classrooms is needed to result in improved language growth, but

correlational (Dickinson & Porche, under review; Dickinson & Tabors, 2001) and experimental studies

(Duggan, et al., 1999; Huttenlocher, et al., 2002; Vasilyeva, et al., 2006; Wasik & Bond, 2001; Wasik, et

al., 2006) have identified promising candidates. If interventions are to improve language outcomes there

may need to be fine-grained ways of specifying and tracking recommended practices, because teachers

facilitate language through use of very particular and subtle methods not well described by global

approaches to examining classroom instruction (Dickinson, Darrow, & Tinubu, 2008; Dickinson,

Flushman, & Freiberg, 2009; Dickinson, Watson, & Farran, 2007).

Although successful interventions have been identified, many questions remain. Most

interventions have not been sufficiently tested, or inadequate evidence is available regarding effectiveness

for specific groups of children. Many were tested one-on-one or in small groups, or delivered by the

researchers or developers, meaning the results may be hard to replicate in natural classroom settings.

Fidelity of implementation of an intervention often conditions the extent to which an intervention affects

child outcomes as demonstrated by interventions such as MyTeachingPartner (Hamre, et al., 2009;

Justice, Mashburn, Hamre, & Pianta, 2008) and Dialogic Reading (Whitehurst, et al., 1994b; Whitehurst,

et al., 1988), but compliance information is not reported in many studies. Also, assessment protocols vary

greatly, and language outcomes may not measured at all or may only include vocabulary. Bilingual

31

language assessments are now available but testing in two languages is often difficult and costly. The

field could benefit from development of alternative accepted assessment taxonomies and protocols

accounting for cultural and linguistic differences (Campbell, Dollaghan, Needleman, & Janosky, 1997;

Craig & Washington, 1994, 2000; Pena & Quinn, 1997). Finally, there are few longitudinal studies, even

though descriptive studies indicate that the effects of early language support may continue well into the

school years when language becomes especially important to reading success.

Conclusion

In the years from birth to five the rate at which children acquire vocabulary, control of complex

syntax, and ability to use and understand discourse is of considerable long-term importance for academic

success. The rate of acquisition initially is determined by broad features of the child’s environment, but

the proximal factors are the language experiences children have with adults. In the early phase of

acquisition what is most important are opportunities to interact with warm, responsive adults who talk

with children. In the later preschool years children continue to need responsive adults and language

exposure, but the kind of language experiences that yield maximal benefits begins to narrow. For older

children the quantity of exposure alone is not sufficient; rather exposure to lower frequency vocabulary

and more complex syntax is necessary - the kind of language found in books and the kind of language that

can be encountered with talking with adults seeking to stretch children’s language and conceptual

development. We now know environmental factors that limit children’s language growth and we are

beginning to unravel the linkages between early experience and long-term academic success, but we have

far to go in understanding how to deliver interventions on a large scale that reliably result in enough

growth in language to have enduring effects on later academic success.

32

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