phonological acquisition in bilingual spanish–english speaking children

7/25/2019 Phonological Acquisition in Bilingual SpanishEnglish Speaking Children

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Phonological Acquisition in BilingualSpanishEnglish Speaking Children

Purpose:In this study, the authors aimed to determine how between-languageinteraction contributes to phonological acquisition in bilingual SpanishEnglishspeaking children.Method:A total of 24 typically developing children, ages 3;0 (years;months) to4;0, were included in this study: 8 bilingual SpanishEnglish speaking children,8 monolingual Spanish speakers, and 8 monolingual English speakers. Single wordand connected speech samples were obtained for each child. This study examinedinteraction between the two languages of bilingual children during phonological

acquisition through the measurement of (a) transfer(the frequency and types ofphonological transfer present in the speech of bilingual children); (b) deceleration(a slower rate of acquisition for bilinguals as compared with monolinguals); and(c) acceleration (a faster rate of acquisition for bilinguals as compared withmonolinguals.Results:Findings demonstrated that (a) transfer was evident in the productions ofbilingual children, (b) differences were found in accuracy between monolingualand bilingual children, and (c) sound frequency did not predict differential accuracyof either phonetically similar sounds between languages or phonetically dissimilarsounds specific to Spanish or English.Implications:The results from this study indicate that transfer, deceleration, and apossible variation of the acceleration hypothesis occur in bilingual phonologicalacquisition. Evidence was found for separation and interaction between the bilingual

children

s 2 languages (J. Paradis & F. Genesee, 1996).KEY WORDS: phonology, interaction, bilingual, Spanish

S ome studies have found that bilingual children begin with a singlelanguage system that gradually separates into two autonomoussystems (e.g., Leopold, 1970; Schnitzer & Krasinski, 1994; Vogel,1975). This orientation to bilingual language acquisition is referred to as

the unitary system model (USM; e.g., Bhatia & Ritchie, 1999; Genesee,

1989). In contrast, thedual systems model maintains that bilingual chil-

dren develop separate language systems for each language andthat thesesystems do not interact (e.g., Keshavarz & Ingram, 2002). A third possi-

bility is that the two systems of bilingual children do interact (Paradis,

2001; Paradis & Genesee, 1996). To account for interaction between lan-

guages, Paradis and Genesee (1996) proposed a series of interdependence

hypotheses in an attempt to determine how bilingual children acquire

their two language systems.Interdependence has been defined as transfer,

deceleration, and accelerationin bilingual language acquisition(Paradis &

Genesee, 1996). Hereafter, this notion of interdependence in acquisition

will be referred to as interaction. The present study investigates inter-

action specifically in the area of phonological acquisition.

Leah Fabiano-SmithState University of New York at New Paltz

Brian A. GoldsteinTemple University, Philadelphia, PA

Journal of Speech, Language, and Hearing Research Vol. 53 160178 February 2010 DAmerican Speech-Language-Hearing Association160


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TransferParadis and Genesee (1996) hypothesized that con-

sonants and/or vowels that are specific to one language

will transfer to productions of the other language. This

is known as segmental transferan example would be

when a bilingual SpanishEnglish speaking child uses

the approximant /a/, a sound specific to English, in theproduction of a Spanish word (e.g., carro /karo/ Y

[kaao]). Transfer has been found to occur in a bi-directional

mannerthat is, from English to Spanish as well as from

Spanish to English. Researchers who investigate bi-

lingualism have argued that bilingual childrens rates

of transfer may be indicative of interaction between their

two languages (Keshavarz & Ingram, 2002; Paradis,

2001). A number of studies have examined this issue.

For example, in a study on one of their SpanishEnglish

speaking sons (from ages 1;6 [years;months] to 4;6),

Schnitzer and Krasinski (1996) found a low frequency

(i.e., few tokens) of phonological transfer between their

childs two languages, indicating a low level of between-

language interaction. Keshavarz and Ingram (2002), in

their case study of a FarsiEnglish bilingual child, found

some specific examples of transfer, although it was not

widespread from either English to Farsi or vice versa.

Thus, they concluded that the evidenced transfer was in-

dicative of two language systems that were not entirely

separate from one another. In another study, Fabiano

and Goldstein (2004a) compared two typically develop-

ing (TD) 4-year-old SpanishEnglish speaking children

(one who was undergoing bilingual first language acqui-

sition (BFLA) and one who was a sequential bilingual

child) and two 4-year-old SpanishEnglish speaking chil-dren with phonological disorders (PDs; one who was un-

dergoing BFLA and one who was a sequential bilingual

child). Three occurrences of segmental transfer were

found, with all occurrences being produced by the 2 bi-

lingual children withphonological disorders. In a follow-up

study, Fabiano and Goldstein (2004b) examined 2 ad-

ditional bilingual children undergoing BFLA (one TD

and one with a PD) following the same methodology as

discussed in their 2004a study. They found one occur-

rence of segmental transfer in the child who presented

with a PD yet no instances of either prosodic or syllabic

transfer. Paradis (2001) compared 17 FrenchEnglishspeaking children undergoing BFLA, ages 2335 months,

to 18 French monolingual and 18 English monolingual

speakers on sound and syllable production. In the bi-

lingual childrens productions, she found that the stress

patterns of French influenced initial syllable stress

patterns of English; however, the bilingual childrens

stress patterns on weak syllables were identical to the

patterns of monolingual children. Paradiss (2001) con-

clusion was that for many of the bilingual children, in-

teraction was occurring infrequently between their two

languages.

Past studies examining transfer in bilingual chil-

dren indicated that at least some transfer exists from

one language to the other. Previous studies, however

with the exception of Paradis (2001)have yet to exam-

ine patterns of between-language transfer across groups

of bilingual speakers. A multiple-subject design is needed

to examine patterns of phonological acquisition across, as

well as within, bilingual children.

DecelerationFortheir second hypothesis, deceleration, Paradisand

Genesee (1996) predicted that aspects of phonological de-

velopment emerge at a slower rate in bilingual children

than in monolingual children.1 The premise behind thede-

celeration hypothesis is that interaction between the two

languages of bilinguals interferes with acquisition and

thus results in poorer linguistic skills in bilinguals com-

pared with monolinguals. Some evidence for this hy-

pothesis has been found in studies comparing bilingual

children withmonolingual children in the domains of syn-

tax and morphology (e.g., Swain, 1972; Vihman, 1982)

and, more recently, phonology (Gildersleeve-Neumann,

Kester, Davis, & Pea, 2008).

Gildersleeve-Neumann et al. (2008) examined the

English phonological skills of TD, bilingual English

Spanish speaking 3-year-olds. The results revealed that

although the bilingual children exhibited phonetic in-

ventories in English that fell within the normal range for

their monolingual English-speaking peers, they also dem-

onstrated lower accuracy than monolinguals. Therefore, as

compared with their English-speaking peers, the bilingual

children in their study demonstrated a slower rate ofdevelopment, as measured by accuracy of production.

Goldstein and Washington (2001) compared 4-year-old

SpanishEnglish bilinguals to their age-matched mono-

lingual peers in both Spanish and English. The bilingual

children in their study were much less accurate than

monolingual speakers on three Spanish sound classes

(spirants, flap, and trill) but exhibited skills within the

normal range formonolingual speakers on all other sound

classes. Therefore, there is some evidence in previous

work that the rate of acquisition for bilinguals might be

slower when compared with their monolingual counter-

parts, at least on measures of accuracy.

AccelerationFor their third hypothesis, Paradis and Genesee

(1996) posit that certain properties in the grammar2 of

1For their second hypothesis, Paradis and Genesee (1996) used the term

delayto refer to cases in which language abilities acquired by monolingual

children are acquired at a later age by bilingual children. Although Paradis

andGenesee (1996)did notintend to suggestimpairment in their discussionof

bilingual acquisition, the termdelaymight connote some level of impairment.

Thus, here, thedelayhypothesis is termed deceleration.2The termgrammaris used here in the broad sense to include phonology.

Fabiano-Smith et al.:Phonological Acquisition in Bilingual Children 161


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bilingual children emerge at a faster rate in bilingual

children relative to age-matched monolinguals. The prem-

ise behind the acceleration hypothesis is that interaction

between the two languages of bilingual children aids in

the acquisition process and thus results in superior lin-

guistic skills in bilinguals compared with monolinguals.

A number of studies have shown support for this hypoth-

esis as well. Specifically, Tracy (1995) and Gawlitzek-Maiwald and Tracy (1996) examined GermanEnglish

bilingual children and observed that certain structural

properties of German allow for faster acquisition of some

structural properties in English. For example, they found

that one of the bilingual children in their study, Hannah,

acquired English infinitival phrase structure at a faster

rate than did age-matched monolingual English-speaking

children. Similarly, Kehoe, Trujillo, and Lle (2001) and

Lle, Kuchenbrandt, Kehoe, and Trujillo (2003) exam-

ined interaction between the two languages of Spanish

German bilingual children. They found that acquisition

of German resulted in faster acquisition of coda conso-nants in the Spanish productions of bilingual children as

compared with theirmonolingual Spanish-speakingpeers.

The authors concluded that interaction between German

and Spanish led to acceleration in bilingual phonological

acquisition. These findings demonstrated that bilingual

children may, at times, show a faster rate of acquisition

for some language constructs when compared with their

monolingual peers.

A Variation of Acceleration

Previous studies have found evidence of transfer,deceleration, and acceleration in bilingual acquisition.

However, there is no hypothesis that accounts for re-

sults of studies that have found bilingual children to

demonstrate rates of acquisition that fall within the

normal range for monolingual speakers of both languages

(DeHouwer, 1995; Goldstein, Fabiano, & Washington,

2005; Goldstein & Washington, 2001 [for phonology];

Nicoladis, 1994; Padilla & Liebman, 1975 [for morpho-

syntax]; Paradis & Genesee, 1996). Demonstrating such

a rate of acquisition at a given point in development

might be indicative of interaction between a bilingual

childs two languages. Perhaps one language might beaiding in the acquisition of the other, allowing for a rate

of acquisition in bilinguals that falls within the normal

range for monolingual children of the same age. This

possibility could provide evidence for a variation of the

acceleration hypothesis.

For instance, Paradis and Genesee (1996) examined

the syntactic skills of three bilingual FrenchEnglish

speaking children undergoing BFLA (ages 1;11-2;2). Spe-

cifically, the authors examined functional categories,

as this construct is acquired earlier in French than in

English. They found that the bilingual children in their

study were acquiring the targeted aspect of syntax at the

same rate as that of their monolingual peers. In another

study, Goldstein and Washington (2001) examined the

English and Spanish phonological skills of TD, 4-year-

old bilingual children and found no significant differ-

ences between bilingual and monolingual children on

percent correct consonants, percent correct consonants

for sound classes, or percentage of occurrence of pho-nological patterns. The results of their study indicated

that the overall phonological skills of bilingual 4-year-

olds were similar to those of monolingual children in

both languages. Similarly, Goldstein et al. (2005) exam-

ined the phonological skills of TD 5-year-old bilingual

SpanishEnglish speaking children and compared them

with their age-matched monolingual peers. The authors

found no significant difference between bilingual and

monolingual children on segmental accuracy, syllabic

accuracy, or percentage of occurrence of phonological

patterns. These findings indicate that bilingual children

are maintaining a rate of acquisition that is similar tothat of their monolingual peers. Thus, the relative load

of two inputs is not resulting in acquisition for bilinguals

that occurs at a slower rate, nor is one language aiding

the other to the extent that acquisition is occurring at a

faster rate. Rather, interaction between the two languages

of bilingual children leads to a rate of development that

is within the normal range of their monolingual peers.

It is important to highlight that bilingual children

can exhibit characteristics of transfer, deceleration, and

a variation of acceleration simultaneously. For exam-

ple, Fabiano-Smith and Barlow (2009) examined 8 bilin-

gual Spanish

English speaking children (ages 3;0-4;0)and compared them to their monolingual, age-matched

peers. An accuracy analysis and a typological analysis of

phonetic inventories were performed in order to identify

instances of transfer, deceleration, and acceleration. They

found that even though the bilingual children demon-

strated lower accuracy of production when compared

with monolinguals, their phonetic inventories were just

as complex in both languagesas the phonetic inventories

of monolingual speakers of either language. The bilin-

gual children acquired two complex phonetic inventories

at the same rate that the monolingual children acquired

only one (i.e., a variation of acceleration). The authorsalso found instances of transfer in the productions of

many of the bilingual children. These results indicate

that examining one phonological construct may provide

evidence for deceleration, but examining other phono-

logical constructs may provide evidence for a variation

of acceleration and/or transfer. Thus, it is possible for

transfer, deceleration, and a variation of acceleration to

exist in development simultaneously.

It is necessary, then, to determine what bilingual

children implicitly knowabout the sounds in the two

languages they are acquiring (Watson, 1991). It may be

162 Journal of Speech, Language, and Hearing Research Vol. 53 160178 February 2010


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possible to provide evidence for Paradis and Genesees

(1996) hypotheses by determining how accurately bi-

lingual SpanishEnglish speaking children produce

sounds that are phonetically similar between their two

languages (referred to here as shared sounds) versus

sounds that are phonetically dissimilar and language spe-

cific (referred to here as unsharedsounds; see Table 1).

The examination of shared and unshared sounds couldalso provide evidence for how bilingual children achieve

rates of acquisition that fall within the normal range

for monolingual children (i.e., a variation of the accel-

eration hypothesis).

Phonetic SimilarityOur notion of shared versus unshared sound accu-

racy is adapted from the literature on the relevance of

phonetic similarity on second language (L2) phonolog-

ical acquisition (Flege, 1981, 1987). L2 learners have

little difficulty in the perceptual categorization of second-

language sounds that are phonetically similar to those in

their native language (L1; Flege, 1981). L2 learners often

perceive L2 speech sounds in terms of their L1 phonemic

categories (Flege, 1987). This may account for why speak-

ers extend the production of already familiar sounds into

new (L2) phonetic contexts. Thus, there seems to be a sys-

tematic interaction between the two languages of the L2

speaker, reminiscent of Paradis and Genesees (1996)

notionof interaction between the two language systemsof

bilingual children.

Fleges (1981) notion of sound categorization in adult

L2 acquisition could be occurring in bilingual phonolog-ical acquisition in a similar way. Just as Flege posits for

L2 learners, we hypothesize that bilingual children per-

ceive phonetically similar sounds as common between

their two languages and categorize them into the same

phonemic category despite their fine phonetic distinc-

tions (e.g., aspiration on stops). The result of this cate-

gorization, according to our prediction, is that sounds

that are phonetically similar between the two languages

are more quickly accessed and therefore extended intothe phonetic contexts of both languages. Bilingual chil-

dren would then have more production experience with

these phonetically similar (i.e., shared) sounds than with

phonetically dissimilar (i.e., unshared) sounds, thereby

influencing accuracy. Bilingual children may reduce the

use of allophonic variants of a shared phoneme, but the

essential features of that phoneme remain intact (i.e.,

voicing, place, and manner). That is, another phoneme

is not substituted for the target sound, which would

thereby result in a production error. Rather, bilingual

children may use the same sound in both language con-

texts because doing so does not interfere with the sounds

ability to mark distinctions between words (e.g., /p/ in

both English and Spanish carries the same function).

This, in turn, may lead to an increase in rate of ac-

quisition of these phonetically similar sounds. Bilingual

children could be using one sound in productions of both

languages due to interaction between their two lan-

guages. The interaction occurring between the bilingual

childs two languages that allows for quicker access of

phonetically similar sounds could lead to more experi-

ence in production and an increased rate of acquisition

(i.e., a variation of acceleration that allows bilinguals to

demonstrate a rate of acquisition that falls within thenormal range of monolinguals).

Table 1.Shared and unshared sounds between English and Spanish.

Sound classes Shared sounds Unshared sounds specific to EnglishUnshared sounds

specific to Spanish

Plosives /p/, /b/, /t/, /d/, /k/, /g/Nasals /m/, /n/ nasal /:/ //Fricatives /f/, /s/, /8/* /v/, /Z/, /z/, /S/, /q/, /h/Spirants* [b], [S]Affricate /^/ /u/

Lateral liquid /l/Nonlateral liquid /a/Glides /w/, /j/**Flap /R/Trill /r/

*The voiced interdental fricative /8/ is phonemic in English but allophonic in Spanish. It is being analyzed assharedbecause phonologists are divided over which group of soundsspirants or voiced stopsis theunderlying form. For example, Barlow (2003) argues that the spirant [8] in Spanish may actually be theunderlying form and not the phonetic realization of /d/; thus, it was included in the shared sound category.**Glides were analyzed as part of the vowel nucleus for Spanish (Harris, 1993); thus, they were not included inanalyses of accuracy for either English or Spanish.



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This concept of sound categorization for L2 speakers

has been generalized into the context of bilingual chil-

dren in previous studies examining the accuracy of shared

and unshared sounds. Goldstein, Fabiano, and Iglesias

(2003) examined 5 TD sequential bilingual Spanish

English speaking children (children whose L1 is Spanish

and began exposure to English at age 3;0) and 5 sequen-

tial bilingual children with PD (ages 4;0-7;0).They foundhigher accuracy (a) on shared sounds and syllable types

than on unshared sounds and syllable types and (b) on

manner classes that possessed more shared sounds than

on mannerclasses that possessed more unshared sounds.

In addition, high accuracy on shared sounds was found

independent of the effect of developmental sequence

that is, bilingual children were not more accurate on

shared sounds simply because these sounds tended to be

acquired earlier than unshared sounds. This result was

found across the two languages and language ability

groups.

Frequency of Occurrenceof Shared Sounds

It is possible that, as with L2 speakers, bilingual

children are perceiving equivalence (Flege, 1981) for

overlapping phonological properties of their two lan-

guages and thus are establishing a single phonemic cat-

egory for particular sounds that occur in both languages

(i.e., shared sounds). At the same time, they may main-

tain separate phonemic categories for those that only

occur in one language (i.e., unshared sounds). That is,

bilingual children may be more accurate on sharedsounds because these sounds are used in both language

contexts. This differential accuracy between shared and

unshared sounds may be evidence for and may account

for how bilingual children demonstrate rates of acquisi-

tion that are within the normal range for monolingual

peers in both languages. Sound accuracy, however, might

be predicted by frequency of occurrence of shared sounds.

Although the influence of developmental sequence did

not influence high accuracy of shared sound production

(Goldstein et al., 2003), it is possible that frequency of

occurrence of shared sounds does serve as a predictor.

The investigation of frequency was incorporatedinto the current study in an attempt to examine the

effect of frequency of occurrence of shared sounds on the

accuracy of production of shared sounds. Sounds that

are frequently occurring in a language are thought to be

highly unmarked sounds (Cysouw, 2003). High frequency,

in other words, is related to low complexity (Greenberg,

1966; Jakobson, 1941, 1968; Trubetzkoy, 1939). Previous

studies have found that frequently occurring sounds are

produced with higher accuracy than sounds that are sig-

nificantly less frequent. Indeed, Kirk and Demuth (2003)

reported that English-learning children acquired the

more frequent coda clusters before the less frequent on-

set clusters. In addition, high frequency stop + /s, z/ clus-

ters were acquired before other, less frequent phoneme

combinations.

At issue is whether high accuracy of shared sounds

in bilingual speakers is a result of frequency of occur-

rence of those sounds in a language, given that speech

sound accuracy and frequency are related, at least cross-linguistically (Demuth, 2001; Levelt, 2000; Roark &

Demuth, 2000; Stemberger & MacWhinney, 1986).

Sounds in the shared category could be produced more

accurately than sounds in the unshared category simply

because they occur more frequently in thebilingualstwo

languages and not because of interaction between the

bilinguals two languages. If frequency of occurrence is a

positive predictor of accuracy, then it will not be neces-

sary to invoke notions of interaction to account for the

more accurate productions of shared over unshared

sounds. Thus, the predictive capability of frequency of

occurrence of sounds in each language on accuracy ofshared sounds was examined in the present study.

PurposeThe purpose of this study was to determine how

between-language interaction contributes to phonolog-

ical acquisition in bilingual SpanishEnglish speak-

ing children. Three research questions motivated this

investigation.

Research Question 1: Will bilingual children demon-strate evidence of interaction between their two languages

(i.e., transfer, deceleration, and acceleration) as predicted

by Paradis and Genesee (1996)?The type and frequency

of segmental transfer between the two languages of these

bilingual children will illustrate if, and to what extent,

this type of interaction occurs. Furthermore, lower ac-

curacy in the productions of bilinguals compared with

monolinguals will provide evidence for a slower rate of

acquisition in bilingual children (i.e., deceleration). Con-

versely, significantly higher accuracy in the productions

of bilinguals as compared to monolinguals will provide

evidence for a faster rate of acquisition in bilingual chil-

dren (i.e., acceleration).

Research Question 2: Will bilingual children demon-

strate evidence for a variation of the hypothesis of accel-

eration due to phonetic similarity (Flege, 1981)? Higher

accuracy of bilingual childrens productions on shared

sounds than on unshared sounds, paired with the ab-

sence of this pattern in monolingual children, could pro-

vide evidence for between-language interaction and a

variation of the hypothesis of acceleration.

Research Question 3: Does sound frequency of oc-

currence predict high accuracy of shared sounds in the



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productions of bilinguals? Frequency of occurrence of

sounds in a language could motivate high accuracy of

shared sounds. If frequency of occurrence predicts high

accuracy of shared sounds, then between-language in-

teraction could not account for the higher accuracy of

shared sounds as compared with unshared sounds.

MethodParticipants

Twenty-four TD children (ages 3;04;0) were included

in the present study. Children in the United States who

participated in the study were enrolled in a Head Start

program for which there is an income requirement; thus,

socioeconomic status (SES) was controlled for, despite the

fact that maternal education differed. Six of the 8 children

recorded in Mexico were from low-income households; the

2 remaining participants were the children of university

instructors (see the Results section for further details on

the childrens SES and phonological skills).

The children were categorized into three groups

based on language history: (a) eight bilingual Spanish

English speaking children (mean age = 3;6; range =

3;04;0); (b) eight monolingual Spanish speakers (mean

age = 3;4; range = 3;24;0); and (c) eight monolingual

English speakers (mean age = 3;3; range = 3;03;11). A

KruskalWallis nonparametric test (Kruskal & Wallis,

1952) indicated no significant difference between the

groups based on age, c2(2,N= 24) = 3.55,p = .169. An ex-

tensive parent and/or teacher report was used to deter-

mine each child

s language status (i.e., monolingual orbilingual) and phonological ability (i.e., to ensurethat all

children were TD with no speech, language, cognitive, or

neurological deficits).

Bilingual participants. Demographic characteris-

tics of the bilingual participants can be found in Table 2.

The bilingual children were speakers of Puerto Rican

and Dominican Spanish. This study took place during

May and June, and the children had been enrolled in a

bilingual Head Start program since the beginning of the

school year. Percent input and output were determined

for both languages through parent report (after Restrepo,

1998). All bilingual participants received at least 20%

input in both languages andproduced at least 20%outputin both languages. This criterion follows from previous

work, which has shown that children need at least 20%

exposure in order to use the target language (Pearson,

Fernandez, Lewedeg, & Oller, 1997). The first author

asked parents to describe his or her childs schedule on a

typical day. The childs activities, the interlocutor(s) in-

volved, and the language typically used duringthat activ-

ity were recorded. The number of hours of exposure to

each language per day, Monday through Friday, was de-

termined (i.e., input). The same method was used to de-

rive the number of hours the child used each language

duringthe workweek (i.e., output). Similarquestions wereasked regarding the childs weekend schedule. Overall

percentages of language use were calculated separately

by multiplying the number of hours of exposure (input)

or use (output) by 100, then dividing that number by the

total number of hours in the week. In addition, parents

rated their childrens proficiency in both English and

Spanish on a scale from 0 (child could not speak the indi-

cated language at all) to 4 (child had native-like profi-

ciency in the language; Pea, Bedore, & Rapazzo, 2003;

Pea, Bedore, & Zlatic-Giunta, 2002).All childrenincluded

in the present study were rated as either 3 or 4 by their

parents in both English and Spanish, indicating native ornear native-like competence in the indicated languages.

North Philadelphia, where the bilingual data were

collected, is a bilingual, Puerto Rican community that has

maintained the use of both English and Spanish for more

than 40 years. All children living in this community have

Table 2.Demographic data on bilingual participants.

ChildID

CA (M= 3;5)[years;months] Gender

Motherseducation

Percent inputSpanish

Percent outputSpanish

Percent inputEnglish

Percent outputEnglish

ProficiencySpanish

ProficiencyEnglish

B01 3;8 Male High school 63 63 37 37 4 3B02 3;5 Male High school 75 75 25 25 4 3B03 3;8 Male Some

university58 30 42 70 3 3

B04 3;5 Male Bachelor sdegree

50 20 50 80 3 4

B05 3;8 Female High school 40 20 60 80 3 4B06 3;4 Male Some


B07 3;11 Male High school 40 20 60 80 3 4B08 3;5 Male Some




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some English exposure before entering school, even if

Spanish is theonly language spoken in the home. The na-

ture of the community and the large amount of English

input that the children receive within the school system

could account for rapid acquisition of English upon enter-

ing preschool. Parent report was also used to determine

the length of exposure to each language for all bilingual

speakers. Each child was determined to have had mostlySpanish input and output in the home up to age 3;0, after

which English exposure began at preschool, or they re-

ceived exposure to both languages in the home from birth.

Thus, all bilingual children were categorized as early

bilinguals(Genesee, Paradis, & Crago, 2004).

Monolingual participants.Demographic characteris-

tics of the monolingual Spanish and monolingual English

participants are found in Table 3. Datafrom 8 monolingual

Spanish speakers were collected in Quertaro, Mexico,

and data from 8 monolingual English speakers were

collected in Philadelphia, Pennsylvania. Children in

each monolingual group had no input or output in anylanguage other than their native language. To be in-

cluded in the study, the monolingual children s pro-

ficiency rating (obtained through parent report) in

their language had to be either 3 or 4. Monolingual

children were included in this study in order to obtain

developmental information for each language and to

compare the accuracy of sound production and the sub-

stitution patterns between monolingual and bilingual

speakers.

Data CollectionBoth single word and connected speech samples

were collected from each child for analysis. Single word

samples were used for phonological analyses. Connected

speech samples were used to provide background in-

formation on the childrens language skills. If a sound

production was not found in the single word sample, con-

nected speech aided in the phonetic inventory analy-

sis. Each bilingual child was recorded in Spanish and

English, and each monolingual child was recorded in

his or her respective language.

The phonology subtest of the Bilingual English Span-

ish Assessment (BESA; Pea, Gutirrez-Clellen, Iglesias,

Goldstein, & Bedore, 2005), was used to elicit sounds

in single words. The assessment contains 31 separate

target items for English and 28 separate target items

for Spanish. This assessment has been used previously

with bilingual children (e.g., Goldstein & Washington,

2001; Goldstein et al., 2005). Each target item was elic-

ited via a spontaneous label made in reference to a

photograph. If the child did not label the photograph

spontaneously, the function of the item was provided to

thechild. If thechildstill did not label theitem, delayed

imitation was used because of the negligible difference

between spontaneous and imitative forms (Goldstein,

Fabiano, & Iglesias, 2004).

A pre-determined set of toys whose names targeted

English andSpanish consonant soundswas used to elicit

a conversational speech sample from each bilingual child

in English and Spanish and from each monolingual child

in English or Spanish. Each single word and connected

speech sample was recorded using The Presenter wire-

less lapel microphone, transmitter (Model T1-CL), and

receiver (Model T3-CL; Shure, Inc., Niles, IL) with inputinto a Dell Latitude 100L computer using a Creative

Labs Sound Blaster Audigy 2-Z5, 24-bit sound card.

Table 3.Demographic data on monolingual participants.

Child ID CA Language Gender Mother s education Parent concern Clinician concern

S 01 4;0 Spanish Male Some high school No NoS 02 3;3 Spanish Male Master s degree No NoS 03 3;3 Spanish Male High school diploma No NoS 04 3;10 Spanish Male Some high school No No

S 05 3;2 Spanish Female Bachelor s degree No NoS 06 3;6 Spanish Female Master s degree No NoS 07 3;4 Spanish Female Some high school No NoS 08 3;4 Spanish Male Some high school No NoE 01 3;3 English Female Master s degree No NoE 02 3;1 English Female Medical degree No NoE 03 3;11 English Female Master s degree No NoE 04 3;8 English Male High school diploma No NoE 05 3;0 English Male Bachelor s degree No NoE 06 3;0 English Male Bachelor s degree No NoE 07 3;1 English Male Bachelor s degree No NoE 08 3;7 English Male Master s degree No No



8/20

AnalysesData from the single word samples were phoneti-

cally transcribed with diacritics using the International

Phonetic Alphabet (IPA). Dialectal features of Puerto

Rican, Mexican, and Dominican Spanish (e.g., in Span-

ish, [x] for /r/ in perro) and English (e.g., [n] for /:/ in

going

) consonants were taken into account and were

not scored as errors.

Reliability of TranscriptionSingle word samples. Reliability of transcription

was performed on the single word samples between two

primary transcribers (bilingual graduate students in

speech-language pathology [SLP] at Temple University,

Philadelphia, Pennsylvana) and the first author of this

study, who is an EnglishSpanish bilingual. Both the

first author and the bilingual graduate students were

trained in narrow transcription using the IPA. The twobilingual graduate students phonetically transcribed all

of the single word samples. The first author then per-

formed interjudge reliability on those transcriptions; in

addition, the original transcribers performed intrajudge

reliability on their own transcriptions. Since three judges

were involved in the reliability process, when a disagree-

ment occurred between two of the judges, the third judge

was called in to make a decision. The decisions made by

the third judge were accepted in the final transcriptions.

Intrajudge and interjudge reliability of IPA narrow tran-

scription was calculated for 100% of the Spanish and

English target words on the single word assessment forall of the children.

For the Spanish monolingual group, reliability

reached 99.16% and 98.74% for intra- and interjudge

reliability, respectively, for the single word samples. For

the English monolingual group, reliability reached 98.7%

and 96.94% for intra- and interjudge reliability, respec-

tively. For the Spanish samples of the bilingual chil-

dren, reliability reached 99.14% and 97.48% for intra- and

interjudge reliability, respectively. Finally, for the En-

glish samplesof the bilingual children, reliability reached

98.61% and 95.67% for intra- and interjudge reliability,

respectively.

Because the reliability rates were higher than those

reported in similar studies, we conducted an additional

reliability check on 10% of the sample to be certain that

our estimateswere correct. A bilingual SpanishEnglish

speaking student in SLP at San Diego State University

(who was unfamiliar with this particular single word

probe and who was trained in IPA narrow transcription)

performedinterjudge reliability. Reliability of transcrip-tion performed by this additional judge reached 98.44%

for the monolingual Spanish samples (10 disagreements

out of 640 opportunities), 99.54% for the monolingual

English samples (3 disagreements out of 651 opportuni-

ties), 98.59% for the Spanish productions of bilinguals

(9 disagreements out of 634 opportunities), and 98.47%

for the English productions of bilinguals (10 disagree-

ments out of 650 opportunities).

Connected speech samples. The connected speech

samples were used to provide background information

on each childs language skills and to obtain three oral

language measures: mean length of utterance in mor-phemes (MLUm); number of different words (NDW),

and total number of utterances (TNU; see Table 4). Data

from the connected speech samples were transcribed or-

thographically into communication units (C-units). The

language transcripts were analyzed using the System-

atic Analysis of Language Transcripts (SALT [Beta V9

program]; Miller & Iglesias, 2006) to obtain grammat-

icality measures. Interjudge reliability of orthographic

transcription was performed between a bilingual SLP

graduate student and the first author. Interjudge relia-

bility was calculated on 100% of the utterances in the

English and Spanish connected speech samples for allchildren. Reliability of transcription reached 93.67% for

the monolingual Spanish speakers, 98.27% for the mono-

lingual English speakers, 98.06% for the Spanish produc-

tions of bilinguals, and 96.39% for the English productions

of bilinguals.

The results from analyses examining the childrens

connected speech samples showed that their oral lan-

guage skills were commensurate with published norms

for monolingual English (Bland-Stewart & Fitzgerald,

2001) and monolingual Spanish speakers (Bedore, 2005).

The results are also commensurate with norms accom-

panying the Bilingual Spanish

English SALT (Miller &

Table 4. Means and standard deviations for grammatical characteristics of monolingual and bilingual children.

Language GroupsMean length of

utterance (MLUm)Number of different

words (NDW)Total number ofutterances (TNU)

Monolingual Spanish speakers 2.38 (SD= 0.61) 91.25 (SD= 41.75) 100.37 (SD= 53.07)Spanish productions of bilinguals 2.25 (SD= 0.62) 103.75 (SD= 46.27) 135.25 (SD= 65.13)Monolingual English speakers 3.57 (SD= 0.75) 221.62 (SD= 58.49) 216 (SD= 68.27)English productions of bilinguals 2.70 (SD= 0.91) 123.62 (SD= 58.47) 144.12 (SD= 61.09)



9/20

Iglesias, 2006) program for both Spanish and English

productions of the bilingual children. All children scored in

the typical range for grammatical characteristics for their

age and language status (i.e., monolingual or bilingual).

Phonetic Analyses

Analyses of the single word samples for all threegroupsmonolingual Spanish-speakers, monolingual

English speakers, and bilingual SpanishEnglish

speakerswere performed using Logical International

Phonetic Programs (LIPP; Oller & Delgado, 2000) to de-

termine the phonological skills of each child. A phonetic

analysis was performed on the childrens productions of

segments overall. Specifically, phonetic inventories were

constructed to determine what sounds each child had

acquired. If a child produced a particular sound two or

more times, regardless of whether it occurred as a cor-

rect production in a word or as a substitute in another

word, that child was said to possess that sound in his or

her inventory (Elbert & Gierut, 1986). If a target did not

occur at least twice, that sound was not included as part

of the childs inventory.

A substitution error analysis was performed on the

productions of the bilingual speakers to determine what

sounds the children were using as substitutes. Given our

interest in transfer, if bilingual children used language-

specific soundsin the productions of their other language,

those substitutions were not counted as errors. To that

end, two analyses were completed (see next paragraph).

Context-free inventories were obtained from LIPP

for each child, in each language. Each sound target, thenumber of times that target occurred, and the sounds

produced for that target were listed for each inventory.

Both correct productions and substitution errors were

recorded. First, an analysis determining the quantity

(i.e., frequency) of phonological transfer was completed.

Instances of phonological transfer were recorded when

an unshared, or language-specific, sound appeared in

the other language (e.g., the Spanish /r/ substituting for

the English liquid /a/ in an English production) or when

a fine phonetic distinction specific to one language was

found in the production of the other language (e.g., aspi-

ration of /p/ in a Spanish production). Next, an analysis

examining the quality (i.e., type) of transfer was per-

formed. Instances of transfer were examined for (a) over-

all patterns or preferences that the children were using

(i.e., whether they used certain language-specific sounds

as substitutes and not others), (b) the language-specific

sounds used as substitutes, and (c) the direction of trans-

fer (i.e., Spanish into English or vice versa).

Relational AnalysesOverall accuracy and accuracy by manner class.

Through LIPP, measures of overall percentage of

consonants correct (PCC; Shriberg, Austin, Lewis,

McSweeney, & Wilson, 1997) and PCC for each manner

class were obtained. The following manner classes were

analyzed: stops, nasals, fricatives,affricates, liquids, glides,

flap (Spanish only), and trill (Spanish only). Overall ac-

curacy and accuracy of sounds organized by manner class

were calculated for each language group (i.e., bilingual

Spanish productions,bilingual English productions, mono-lingual Spanish productions, and monolingual English

productions) to determine if bilingual children were

demonstrating evidence of deceleration and/or a varia-

tion of acceleration.

Accuracy of shared and unsharedsounds. A separate

analysis was performed to examine accuracy of shared

and unshared sounds. For this analysis,the LIPP output

of accuracy for each individual sound was organized into

shared and unshared categories for English and Span-

ish. Mean accuracy and standard deviations were then

calculated for these categories. The productions of both

bilinguals and monolinguals were analyzed in the sameway to determineif differential accuracybetween shared

and unshared sounds was (a) characteristic of phono-

logical skills in bilinguals or (b) characteristic of all chil-

drens phonological skills, regardless of language status

(i.e., bilingual or monolingual).

For these analyses, shared and unshared sounds

were categorized at the phonemic rather than phonetic

level, as described previously in the section on phonetic

similarity (Flege, 1981, 1987). To determine if the differ-

ence between the accuracy of shared and unshared sounds

was significant, a nonparametric MannWhitney test

(Mann & Whitney, 1947) was performed for each of thethree groups of speakers using the following related

samples: (a) PCC of shared sounds and (b) PCC of un-

shared sounds. These analyses were performed on En-

glish and Spanish samples separately.

Analysis of FrequencyA mixed-effects regression analysis was performed

to determine if the frequency of occurrence of sounds in

each language had predictive capability on the accuracy

of shared sounds. This analysis was performed separately

on English and Spanish data. The first step in this se-ries of analyses was to obtain descriptive information for

each participant, thus means and standard deviationsfor

PCC were obtained. A nonparametric alternative to the

analysis of variance (ANOVA), the KruskalWallis test

(Kruskal & Wallis, 1952; and a post hoc Tamahane T2, if

necessary), examining PCC by participant was then

performed to determine if the data from all 8 bilingual

participants were similar and could be collapsed. Fre-

quency of occurrence values were taken from Shriberg

and Kent (1995) for English and Wilson (1984) for Span-

ish, which were used as the frequency measure in the



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statistical analyses. The term frequency here refers to

token frequency, or thenumber of times thesound occurs

in adult productions, representing the childrens input.

The studies from which our frequency values were ob-

tained assigned percent occurrence values to each sound

to represent that sounds frequency in the language. For

example, /s/ was assigned a frequency value of 7.88 in

English and a value of 16.69 in Spanish. The higher thevalue, the more frequent the sound in that language.

Finally, to determine if frequency is a significant pre-

dictor of PCC, a general model was used to analyze the

data through a univariate ANOVA. Because the data for

these analyses were taken from the single word test, lim-

ited opportunities were available for some low-frequency

sounds (e.g., /8/ and / /). Therefore, the data were ana-

lyzed in the mixed model whilerestricting the analyses to

only sounds that had six or more opportunities for pro-

duction. High-frequency and low-frequency sounds were

equally represented in the analysis. English frequency

values ranged from 3.07 to 11.49 (x = 7.30,SD = 3.08), andSpanish frequency values ranged from 3.85 to 16.69 (x=

9.85,SD= 4.51).

The outcome measure was PCC at the sound level.

Frequency was the independent measure, and partici-

pant was the random effect variable. The model took

into account the correlations within each participant.

Model assumptions were checked, and no transforma-

tions were necessary. By taking into consideration the

relationships between all of the variables, the predictive

capability of frequency of occurrence of sounds on the ac-curacy of shared sounds can be interpreted more accu-

rately than with a single correlation.

ResultsPhonetic Analyses

Consonant inventories. Results of the analysis ex-

amining consonant inventories can be found in Table 5.

The independent analysis showed that all bilingual chil-

dren demonstrated phonetic inventories typical of their

chronological age. Many of the bilingual children didnot produce later-developing Spanish sounds such as the

flap, trill, and spirant [8], which is typical for monolingual

Table 5.Sounds not included in the phonetic inventories of the children.

Child ID Produced only once Not produced at all

Monolingual Spanish speakersS 06 /, x/S 07 /g,, r/

Monolingual English speakersE 01 /8/ /q/E 02 /v/ /8/E 03 /S/E 04 /q/ /8, u/E 05 /q, 8, a/E 06 /8, u/E 07 /q, 8/E 08 /q/

Bilingual speakers: Spanish productionsB 02 /x/, [8, S], clustersB 03 //, [b], [S] /x/, [8], /r/B 04 [S] /r/B 05 // /r/

B 06 /x/ [8

], /r/B 07 [b] [8], /R, r/B 08 //, /r/

Bilingual speakers: English productionsB 01 /^, v, z, 8, j/ /:/B 02 /q, 8, u/B 03 /q, u, 8, :/B 04 /z, u/ /8, v/B 05 /8, v/B 06 /S, u/ /v/B 07 /S, u/ /q/B 08 /j/ /q, z, 8/



11/20

Spanish speakers of this age (Acevedo, 1993). In English,

the bilingual group followed a similar pattern as that

of monolingual English speakers, as many did not pro-

duce later-developing sounds such as /q/ and /8/ (Shriberg,

1993).

Transfer. Results of the analysis examining transfercan be found in Table 6. Two of the 8 bilingual children

(25%) produced instances of transfer (nine instances

between the 2 children). They tended to modify low-level

phonetic rules such as the production of an English as-

pirated stop phoneme as unaspirated (e.g., /khA/Y

[ k=A]), as is the rule in Spanish.

Consonant AccuracyResults of the analyses examining consonant accu-

racy can be found in Tables 7 and 8. Results showed that

mean overall PCC was greater than 70% for all groups.

Overall accuracy and accuracy by manner class. The

results for the analysis examining PCC by manner class

can be found in Table 7. To determine if bilingual chil-

dren demonstrated deceleration, acceleration, and/or a

variation of acceleration, a MannWhitney test was per-

formed using overall PCC as the dependent measure.

Language group (i.e., monolingual vs. bilingual) served

as the independent measure. Results indicated thatmono-

lingual children were significantly more accurate than

bilingual children for Spanish (z = 1.99, p = .046) butnot for English (z= 1.73,p = .083). These findings are

suggestive of deceleration in the Spanish productions of

bilinguals. Subsequently, the accuracy of the bilingual

children was compared with the accuracy of monolingual

children from a low SES to eliminate any potential con-

founds (see Figure 1). It was determined that consonant

accuracy was lower in Spanish for all bilingual children

compared with the most accurate monolingual Spanish-

speaking child from a low SES background. Furthermore

consonant accuracy was lower for 5 of the 8 bilingual

children in English compared with the most accurate

monolingual English-speaking child from a low SES back-ground. Overall, bilingual children demonstrated lower

consonant accuracy than their monolingual peers from low

SES backgrounds, suggesting deceleration in bilingual

acquisition (Paradis & Genesee, 1996).

Table 6.Instances of transfer in the productions of bilingual SpanishEnglish speaking children.

Child ID Language context Target Production Substitute used Number of occurrences

B 06 Spanish /negRo/ [negao] [a] 1Spanish /bisikleta/ [bikisikleqa] [q] 1English /t helfon/ [t =elfon] Unaspirated voiceless stop 1English /k ha/ [k=a] Unaspirated voiceless stop 1

English /t host/ [t =ost] Unaspirated voiceless stop 1B 08 Spanish /seoR/ [toR] [] 1

Spanish /gajeta/ [gaZeZa] [Z] 2English /k ha/ [k=a] Unaspirated voiceless stop 1

TOTAL 9

Table 7.Means and standard deviations for percentage of consonants correct (PCC) by manner class.

LanguageGroups Stops Nasals Fricatives Affricates Liquids Glides Flap Trill

MonolingualSpanish

speakers

82.54

(SD= 7.53)

91.80

(SD= 7.8)

79.75

(SD= 9.1)

81.25

(SD= 37.2)

68.75

(SD= 29.88)

100

(SD= 0)

33.33

(SD= 17.81)

37.5

(SD= 34.21)Monolingual

Englishspeakers

88.35(SD= 6.23)

91.91(SD= 6.98)

84.43(SD= 12.85)

75(SD= 34.5)

70.79(SD= 25.64)

87.5(SD= 24.8) N/A N/A

Spanishproductionsof bilingualspeakers

77.40(SD= 9.51)

94.44(SD= 8.39)

66.47(SD= 13.22)

100(SD= 0)

66.98(SD= 25.13)

81.25(SD= 21.67)

25.09(SD= 18.9)

4.1(SD= 11.78)

Englishproductionsof bilingualspeakers

73.31(SD= 14.05)

82.35(SD= 13.33)

63.45(SD= 16.29)

79.16(SD= 24.8)

67.5(SD= 23.45)

83.33(SD= 17.81) N/A N/A



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Table 8.Overall PCC, and PCC for accuracy of shared and unshared sounds.*

Monolingual Spanish speakers

Child ID Overall PCC PCC shared PCC unshared

S 01 78.16 84.21 65.21S 02 73.26 82.0 39.13S 03 68.24 69.64 56.52S 04 82.35 84.21 73.91S 05 68.24 82.45 30.43S 06 80.0 91.37 47.82S 07 72.94 82.45 47.82S 08 69.51 78.18 47.82M (SD) 75.58 (5.49) 81.69 (6.15) 51.08 (13.89)

Monolingual English speakers

Child ID Overall PCC PCC shared PCC unshared

E 01 77.14 87.83 75.00E 02 76.42 80.24 80.00E 03 98.11 100 55.00E 04 75.47 82.71 90.00E 05 84.76 83.75 90.00E 06 81.90 83.75 95.00E 07 93.33 93.75 50.00E 08 85.71 90.00 68.18M (SD) 84.10 (8.20) 87.75 (6.60) 75.39 (16.67)

Bilingual speakers (Spanish PCC data)

Child ID Overall PCCSpanish PCC sharedSpanish PCC unsharedSpanish

B 01 76.54 86.79 47.82

B 02 66.27 75.00 33.33B 03 58.14 66.66 23.80B 04 69.77 84.74 31.81B 05 69.77 77.96 40.90B 06 69.41 77.58 50.00B 07 59.3 72.41 26.08B 08 56.98 66.10 31.81M (SD) 65.77 (6.95) 75.90 (7.54) 35.69 (9.62)

Bilingual speakers (English PCC data)

Child ID Overall PCCEnglish PCC sharedEnglish PCC unsharedEnglish

B 01 72.38 68.75 85.00B 02 57.55 70.00 36.36

B 03 63.81 68.75 50.00B 04 81.90 87.5 70.00B 05 86.67 90.00 75.00B 06 88.57 92.50 85.00B 07 70.48 77.5 50.00B 08 57.14 62.5 45.00M (SD) 72.31 (12.45) 77.18 (11.43) 62.04 (18.99)

*The mixed effects regression analysis utilized data from those sounds with six or more opportunities for production.This table reflects data for all sounds.



13/20

To determine if monolingual and bilingual children

differed in the same way on the accuracy of manner

classes, a MannWhitney test was performed for each

manner class, comparing bilingual to monolingual pro-

ductions. For Spanish, monolinguals demonstrated sig-nificantly higher accuracy than bilingual children on the

following manner classes: trill (z= 2.43,p= .015), frica-

tives (z= 1.99,p= .046), and glides (z= 2.21,p= .027).

For English, monolinguals demonstrated significantly

higher accuracy than bilingual children on stops (z =

2.05, p = .04) and fricatives (z = 2.62, p = .00) only.

Overall, some evidence was found for deceleration in

the bilinguals; however, in general, monolingual and

bilingual children differed only on a minority of man-

ner classes.

Accuracy of shared and unshared sounds. The dis-

tinction betweenaccuracy on shared and unshared soundswas subsequently examined in a separate analysis, the

results of which can be found in Table 8. To determine if

the difference between shared and unshared sound pro-

duction was significantly different within each language

group, a Wilcoxon signed ranks test and effect size anal-

ysis (Cohen, 1988) were performed for each of the four

separate sets of data. Effect sizes were calculated using

Cohens dwith interpretation using the following guide-

lines extant in the SLP literature (e.g., Fiestas & Pea,

2004; 00.10 = negligible; 0.100.25 = small; 0.250.50 =

moderate; 0.500.80 = large; 0.801.00+ = very large).

For the monolingual Spanish group, a significant

difference was found between PCC of shared and un-

shared sounds (z= 2.52,p = .012) with a very large ef-

fect size (d= 2.86) indicating a large difference between

the mean PCC of shared and unshared sounds. A sig-nificant difference was also found for the Spanish of bi-

linguals between PCC of shared and unshared sounds

(z = 2.52,p = .012) with a very large effect size (d = 4.65).

For the monolingual English group, no significant differ-

ence was found between PCC of shared and unshared

sounds (z= 1.82,p = .069) with a very large effect size

(d= 0.97). For the English of bilinguals, however, a sig-

nificant difference was found between PCC of shared

and unshared sounds (z = 2.10, p = .035) with a very

large effect size (d = 0.96). Overall, bilingual children

demonstrated significantly higher accuracy on shared

sounds than on unshared sounds; however, so did mono-

lingual Spanish-speaking children. Upon further anal-

ysis, significant differential accuracy in the monolingual

Spanish-speaking group was the result of very low accu-

racy on flap (33.33%) and trill (37.5%) only.

FrequencyBecause bilinguals (and the monolingual Spanish-

speakers) demonstrated significantly higher accuracy on

shared sounds than on unshared sounds, the following

analyses were performed to determine if the complexity

Figure 1. Comparison of bilingual children to low socioeconomic status (SES) monolingual children onconsonant accuracy.*

*Consonant accuracy for each participant is plotted by Child ID. For bilingual children, the inclusion ofEin the Child ID indicates an English production, and the inclusion of Sindicates a Spanish production.



14/20

parameter of frequency of occurrence of sounds in each

language was motivating high accuracy of shared sounds.

These analyses were performedseparately on the English

and Spanish data.

Spanish productions. The KruskalWallis test per-

formed on PCC by participant yielded a nonsignificant

difference (c2 = 6.55,p = .477,df= 7), indicating that the

participants were not significantly different from one

another on PCC. In order to assess whether frequency

was a significant predictor of PCC, a general linear mixed

model was used with participant as a random effect and

frequency as a fixed effect. The results of this analysis in-

dicated that neither frequency,F(5, 27) = 1.32, p = .284,

nor participant,F(7, 27) = 1.40,p = .243, was a significant

predictor of accuracy. Thus, frequency of occurrence of

sounds in Spanish was not a significant predictor of PCC

in the Spanish productions of bilingual children.

English productions.The KruskalWallis test per-

formed on PCC by participant yielded a significant dif-ference between PCC and participant (c2 = 19.68, p =

.006, df = 7). Because the nonparametric Kruskal

Wallis does not have a post hoc test associated with it,

a one-way ANOVA and post hoc test used for unequal

variancesthe Tamahane T2was used to examine sig-

nificant differences between participants on PCC. The

Tamahane T2 test indicated that participants B07 and

B08 differed significantly on PCC (p = .027). Further

analysis of these 2 participants indicated that child B07

demonstrated the highest percent accuracy on produc-

tion of shared sounds (92.5%), and B08 demonstrated the

lowest percent accuracy on production of shared sounds(62.5%). Both children demonstratedtypical phonological

characteristics for English-speaking 3-year-olds; thus,

data from all 8 children were used for analysis.

To assess whether frequency of occurrence of sounds

was a significant predictor of PCC, a general linear mixed

model was used with participant as a random effect and

frequency of occurrence as a fixed factor. As in the Span-

ish analysis, the data were analyzed in the mixed model

while restricting the analysis to only those sounds that

had six or more opportunities for production. Frequency

of occurrence of sounds was not found to be a significant

predictor of accuracy, F(3, 21) = 1.68, p = .200; however,

participant was found to be a significant predictor of ac-

curacy,F(7, 21) = 3.15, p = .019. Therefore, frequency of

occurrence of sounds in English did not predict high

accuracy of shared sounds in the English productions of

bilinguals. The significance of participant was driven by

the difference in PCC between the child with the highest

PCC (Participant B07) and the child with the lowest PCC

(Participant B08). It should be noted, however, that the

PCC for these children still fell into the typical range for

3-year-olds.

DiscussionThe purpose of this study was to examine how in-

teraction between the two languages of bilinguals con-

tributes to bilingual phonological acquisition. It was

predicted that bilingual children would demonstrate in-

teraction between their two phonological systems, thus

supporting the hypotheses of transfer, deceleration, ac-celeration (Paradis & Genesee, 1996), and /or a variation

of the hypothesis of acceleration. Evidence for these hy-

potheses was examined through (a) transfer, (b) over-

all consonant accuracy and accuracy by manner class,

(c) differential accuracy on the production of shared

and unshared sounds, and (d) the predictive capability

of frequency of occurrence of sounds in each language

on the accuracy of shared sounds.

TransferOverall, 25% of the bilingual children demonstrated

a low frequency of bi-directional transfer. These results

demonstrate that for the most part, bilingual children

maintain separation between their two phonological sys-

tems. Thus, frequency of transfer provided little evi-

dence for interaction between the bilingual childrens

two languages. It seems that these instances of transfer

are not random errors, however. The 2 bilingual children

who demonstrated transfer exhibited systematic modi-

fication of low-level phonetic characteristics. Specifi-

cally, stop consonants were deaspirated in some English

productions. Thus, the bilingual children maintained

separation for the majority of their productions, andbetween-language interaction at this level is rare, sup-

porting Paradis and Genesee (1996).

This finding also informs Fleges (1981) notion of

phonetic similarity in that bilingual children, at times,

abandon fine phonetic distinctions and use phonetically

similar sounds in both languages. For example, the shared

stops /k/ and /t/ were sometimes produced without as-

piration in English, demonstrating that bilingual children

can use the Spanish stops /k/ and /t/ without sacrificing

meaning in their English productions. This finding sup-

ports Flege (1980), who states, [L2] learners frequently

produce a range of different phonetic variants (including

the correct realization) for a single L2 phoneme(p. 117).

DecelerationThe deceleration hypothesis predicts that the rate

of phonological development in bilingual children is

slower than that of monolingual children. Overall con-

sonant accuracy in Spanish was significantly higher in

monolinguals than in bilinguals; however, there was

no significant difference on that construct in English



15/20

between bilingual and monolingual children. When ex-

amined by manner class, bilinguals and monolinguals

differed in accuracy on only a few manner classes. Mono-

lingual Spanish speakers were significantly more accu-

rate than bilingual children on their productions of the

trill, fricatives, and glides. Monolingual English-speaking

children demonstrated significantly higher accuracy than

bilingual children on stops and fricatives. Therefore, theseresults provide some evidence for Paradis and Genesees

(1996) hypothesis of deceleration. Interestingly, the de-

celeration that occurred was not identical across the two

languages. Specifically, the bilinguals showed a slower

rate of acquisition for glides in Spanish but not in En-

glish when compared with monolinguals. Similarly, bi-

linguals showed a slower rate of acquisition for stops

only in English, yet they showed a slower rate of ac-

quisition for fricatives in both languages. It appears

that between the ages of 3;0 and 4;0, some, but not all,

phonological skills in bilingual children are acquired at

a slightly slower rate than for monolingual children ofthe same age. It is important to note that these findings

were independent of the influence of SES (see Figure 1).

The majority of bilingual children demonstrated lower

consonant accuracy in both languages than their mono-

lingual peers from low SES backgrounds.

It is important to point out, however, that the bi-

lingual children in the present study performed within

the typical range for their chronological age, even though

they demonstrated lower accuracy than the monolin-

guals. In Spanish, 5 of the 8 bilingual children demon-

strated overall consonant accuracy greater than 66%.

Jimnez (1987) found that monolingual Spanish-speakingchildren between the ages of 3;0 and 4;0 produce about

half of their consonants accurately. In English, 5 of the

8 bilingual children demonstrated overall consonant ac-

curacy greater than 70%, classifying them in the typical

range for monolingual English speakers their age (Shriberg

& Kwiatkowski, 1982). In addition, sounds produced in

error by these bilingual participants were age appropri-

ate. In their Spanish productions, these bilingual chil-

dren demonstrated errors on flap and trill, errors also

common in monolingual Spanish-speaking preschoolers

(Acevedo, 1993). In English, these bilingual children

demonstrated low accuracy on fricatives, which is alsocommon among monolinguals of the same age (Bauman-

Waengler, 2008). These findings are consistent with pre-

vious studies examining bilingual language acquisition

reporting that bilingual children perform within the typ-

ical range of age-matched monolinguals for grammatical

development (e.g., DeHouwer, 1990; Nicoladis, 1994;

Padilla & Liebman, 1975). Overall, lower accuracy in bi-

lingual production does not indicate delayed or disordered

acquisition in a clinical sense; rather, at some points in

development, bilingual children may exhibit a slower rate

of acquisition; however, that rate still falls within the nor-

mal range for age-matched monolingual children.

AccelerationThe hypothesis of acceleration posits that certain

properties in the grammar of bilingual children emerge

at a faster rate than for monolingual children of the sameage. The results of this study did not provide evidence for

Paradis and Genesees (1996) hypothesis of acceleration

that is, these bilinguals did not demonstrate a faster rate

of acquisition when compared with monolinguals on over-

all accuracy or accuracy by manner class. The findings

of this study support previous studies that have found

evidence of a slower rate of acquisition for bilingual chil-

dren (Gildersleeve-Neumann et al., 2008; Swain, 1972;

Vihman, 1982) and those that have found bilinguals

to demonstrate a rate of acquisition within the normal

range for monolinguals (Goldstein et al., 2005; Goldstein

& Washington, 2001) but not those that have foundbilingual children to be acquiring skills at a faster rate

than their monolingual peers (Kehoe et al., 2001; Lle

et al., 2003).

The bilingual children in the present study did not

demonstrate evidence of acceleration according to its

strict definition. That is, they did not demonstrate a faster

rate of acquisition than that of their monolingual peers;

rather, they demonstrated phonological skills that fall

withinthe typical range for their monolingual peers.It is

possible that this finding is evidence of a variation of the

acceleration hypothesis. Perhaps interaction between

the two languages of the bilingual child results in a sys-tem in which one language is aiding in acquisition of the

other, allowing bilingual children to acquire phonological

skills that fall within the normal range for monolinguals

in both languages.It is also possible that deceleration and

acceleration are occurring simultaneously. More specifi-

cally, these bilingual children demonstrated lower accu-

racy overall than monolingual children; however, these

bilingual children demonstrated accuracy that was still

within the typical range for that of monolinguals. There-

fore, bilingual phonological development could be slower

than that of monolingual children (i.e., deceleration) be-

cause of the relative load of two inputs; however, in-

teraction between the two phonological systems could

counteract that load, maintaining a similar level of pho-

nological skill (i.e., a type of acceleration) in both lan-

guages in comparison to monolinguals.

Phonetic Similarity and Shared SoundsIt was hypothesized in the present study that bi-

lingual children might be using phonetically similar

sounds (i.e., shared sounds) between their two languages

to aid in the rate of acquisition. This phonetic similarity



16/20

between languages could help bilingual children main-

tain phonological skills that fall within the normalrange

for their monolingual peers in both languages, possibly

leading to a variation of the acceleration hypothesis.

That is, properties of one language could possibly aid in

the rate of acquisition of the other language.

In the Spanish and English productions of the bi-

lingual group, a significant difference was found betweenthe accuracy of shared and unshared sounds (with a large

effect size), thus appearing to support our hypothesis.

However, a significant difference was found for the ac-

curacy of shared and unshared sounds in the mono-

lingual Spanish group as well. Further examination of

the data within theSpanishmonolingual group and the

Spanish productions of the bilingual group indicated

that the accuracy of these bilinguals did, in fact, differ

from those of monolingualsbut not in the way that

was expected.

First, the monolingual Spanish-speaking group ex-

hibited a higher standard deviation for PCC of unshared

sounds than did the bilingual children, indicating var-

iation in accuracy of production of unshared sounds.

Bilingual speakers, however, consistently demonstrated

low accuracy on unshared sounds. That is, bilingual chil-

dren exhibited low accuracy on all unshared sounds, and

this pattern was observed across children. Second, the

large difference exhibited by the monolingual Spanish-

speaking group between accuracy on shared andunshared

sounds was due to performance on two specific sounds,

/R/ and /r/. The range of percent accuracy for unshared

sounds in the monolingual Spanish-speaking group was

between 30% and 73%. The range of percent accuracyfor unshared sounds in the Spanish productions of bi-

linguals was between 23% and 50%, which is consider-

ably lower. The bilingual group demonstrated somewhat

equal accuracy across unshared sounds in their Spanish

and English productions, whereas the monolingual speak-

ers demonstrated difficulties with specific unshared

sounds. It should be noted, however, that /R/ and /r/ are

frequently occurring sounds in Spanish. Therefore, it is

possible that low accuracy on these two sounds con-

tributes to the significant effects in the unshared group

for both bilinguals and monolinguals in Spanish. How-

ever, it was observed in this study that frequency did notpredict sound accuracy; thus, this issue should be inves-

tigated further in future studies.

In addition to the findings from the productions of

the monolingual Spanish speakers, large effect sizes were

found between shared and unshared sounds for both bi-

linguals and monolinguals, calling into question if dif-

ferential accuracy of shared and unshared sounds is

evidence of interaction between the two languages of

bilinguals or if monolingual children also demonstrate

this pattern. However, further analysis of shared and

unshared sounds uncovered more differences between

monolingual and bilingual speakers. First, these bi-

lingual children demonstrated a statistically significant

difference between accuracy of shared and unshared

sounds in both languages, and this difference was not sta-

tistically significant for monolingual English-speaking

children. Second, when mean percent accuracy of shared

sounds was compared across bilinguals (75.9% for Span-ish; 77.18% for English) and monolinguals (81.69% for

Spanish; 87.75% for English), there was an accuracy dif-

ference between bilinguals and monolinguals of 10.6%

or less for both languages. More specifically, bilingual

children might produce shared sounds with less accuracy

than monolingual children, but they are within 10 per-

centage points of their monolingual peers in both lan-

guages. Finally, the standard deviation for bilingual

productions on the accuracy of shared sounds is much

smaller (SD= 7.54 for Spanish; SD = 11.43 for English)

than for unshared sounds (SD= 9.62 for Spanish;SD =

18.99 for English), indicating that there is less varia-tion in the production of shared sounds than unshared

sounds, possibly due to phonetic similarity (Flege, 1981).

FrequencyIt was predicted that frequency of occurrence of

sounds in each language might predict high accuracy

of shared sounds. If frequency had been found to pre-

dict high accuracy of shared sounds, high accuracy of

shared sounds would not provide evidence for between-

language interaction (Paradis & Genesee, 1996). High

accuracy of shared sounds, therefore, could not be at-tributed exclusively to interaction between the bilingual

childs two languages.

Results showed that frequency did not predict the

accuracy of shared sounds. This finding is contrary to

previous studies that have found that frequently oc-

curring sounds are produced with higher accuracy than

sounds that are significantly less frequent (e.g., Kirk &

Demuth, 2003). It is possible that the parameter of fre-

quency is not the driving force behind high accuracy of

shared sounds, but other parameters of complexity, yet

to be studied, influence sound accuracy. It is also pos-

sible, as hypothesized in the present study, that highaccuracy of shared sounds is a result of interaction be-

tween the two language systems of bilingual children.

Limitations and Future DirectionsThese results indicate that it is possible to examine

and compare phonological structures within the bilingual

child for evidence of interaction between his or her two

languages. A variation of the hypothesis of acceleration

could possibly be added to complement Paradis and



17/20

Genesees (1996) definition of this hypothesis as an ad-

ditional way to provide evidence for how bilingual chil-

dren acquire two languages. It is also possible that

phonetically similar sounds are not the only phonologi-

cal construct that bilingual children categorize as shared

between their two languages. It is possible that bilingual

children treat the factors related to linguistic complexity,

or rules, of each language in much the same way. Thefindings from the present study provide some evidence

for the investigation of factors such as these in future

research.

The major limitation of the present study is the rel-

atively small number of participants included for statis-

tical analysis. A relatively small number of participants

reduces power; thus, statistical outcomes are suscep-

tible to Type II error. There is inherent difficulty in

matching bilingual participants on chronological age,

input in each language, and output in each language as

well as in assessing 3-year-old bilingual children (de-

pending on the ambient language environment) thatcan produce language samples in both of their languages.

In an attempt to create a homogeneous sample out of a

heterogeneous population, the number of participants

included in the present study was relatively limited.

In future studies, it might be possible to use param-

eters of complexity to predict on which elements in-

teraction and separation will be observed between a

bilingual childs two languages. Frequency of occurrence

of soundsin a languageis often viewed as a factor related

to linguistic complexity, such that sounds that occur

frequently are viewed as less complex than those that

occur frequently (Greenberg, 1966; Trubetzkoy, 1939).Because frequency was not found to be a predictor of

high accuracy of shared sounds, additional parameters

of complexity should be examined to determine at what

level between-language interaction is occurring in bi-

lingual children.

ConclusionRelatively little is known about how typically devel-

oping bilingual children acquire their phonological skills

and even less about if and how the two languages of

bilinguals interact. The findings of this study indicatethat although bilingual children demonstrate separa-

tion between their two phonological systems, those sys-

tems interact to aid in rate of acquisition. Although we

found that bilingual children demonstrated a slower rate

of acquisition than their monolingual peers on some mea-

sures (e.g., phonological accuracy), these skills in the

bilingual children were within the normal range of those

for monolingual children in both English and Spanish. A

similar rate of acquisition between bilinguals and mono-

linguals occurred as well (e.g., on phonetic inventories).

Finally, we found that sound frequency did not predict

accuracy of either phonetically similar sounds between

languages or phonetically dissimilar sounds specific to

Spanish or English. The findings on rate of acquisition

aid in our understanding of the interaction between

(a) the languages of bilingual children and (b) the devel-

opmental similarities and differences between mono-

lingual and bilingual children.

Acknowledgments

We would like to express our gratitude to the children and

families who participated in this project, both in the United

States and Mexico. We thank Ferenc Bunta for assistance in

the selection of recording equipment; Alexandra Hanlon for

consultation on statistical analyses; and Jessica Barlow, Sonja

Pruitt, Skott Freedman, Aquiles Iglesias, MeganDunn Davison

and Ral Rojas for comments on earlier versions of the article.

We express deep appreciation to Donna Jackson Maldonado,

Rosa Patricia Brcenas Acosta, and Martha Beatrz Soto

Martnez at the Universidad Autnoma de Quertaro in

Mexico for their many efforts in the attainment of monolingualparticipants. Finally, we thank the following students who

performed phonetic and orthographic transcription of the data

and participated in analyses of reliability: Jenny Lange,

Monica Krewson, Vanessa Gonzlez, Andrea Fisher, and

Roxanna Palma.

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