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published online 12 November 2013J Learn DisabilMichael J. Kieffer

Learners and Their ClassmatesMorphological Awareness and Reading Difficulties in Adolescent Spanish-Speaking Language Minority

  

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Article

Students from homes in which a language other than the societal language is spoken, a population known as lan-guage minority (LM) learners, are at elevated risk for read-ing difficulties, especially in early adolescence (August & Shanahan, 2006; Snow, Burns, & Griffin, 1998). For LM learners in English-speaking contexts, it is likely that many of these difficulties are due to weaknesses in the domain of English language comprehension (August & Shanahan, 2006). However, it is less clear which specific English lan-guage skills are sources of reading difficulties for adoles-cent LM learners.

One potentially important language skill is morpho-logical awareness (MA), defined as students’ metalin-guistic understanding of how complex words are formed from smaller units of meaning (Carlisle, 1995; Kuo & Anderson, 2006). As a metalinguistic ability that involves the integration of semantic, phonological, and ortho-graphic information (Kuo & Anderson, 2006), MA is likely to be central to the decoding of morphologically complex words and the extraction of meaning from text. Indeed, empirical studies suggest that MA predicts both word reading and reading comprehension for monolin-gual readers (e.g., Carlisle, 2000; Carlisle & Stone, 2005; Deacon & Kirby, 2004; Nagy, Berninger, & Abbott, 2006;

Nagy, Berninger, Abbott, Vaughan, & Vermeulen, 2003; Singson, Mahoney, & Mann, 2000). A growing body of evidence suggests similar relations for LM learners and elective bilinguals (Deacon, Wade-Woolley, & Kirby, 2007; Goodwin, Huggins, Carlo, August, & Calderon, in press; Kieffer, Biancarosa, & Mancilla-Martinez, 2013; Kieffer & Lesaux, 2008, 2012a; Pasquarella, Chen, Lam, Luo, & Ramirez, 2012; Ramirez, Chen, Geva, & Kiefer, 2010).

Given this relation between MA and reading outcomes across the entire ability range, there is reason to believe that weaknesses in MA may be related to reading difficulties. It is likely that incomplete understanding of the morphology system leaves readers ill-equipped to take advantage of the information encoded in morphemes. Evidence supports the notion that monolingual students with reading difficulties demonstrate weaknesses in MA (e.g., Chu, McBride-Chang, Wu, & Liu, 2006; Morris et al., 1998; Tong, Deacon, Kirby,

509968 JLDXXX10.1177/0022219413509968Journal of Learning DisabilitiesKiefferresearch-article2013

1New York University, New York, NY, USA

Corresponding Author:Michael J. Kieffer, New York University, 239 Greene Street, 5th Floor, New York, NY 10003, USA. Email: michael.kieffer@nyu.edu

Morphological Awareness and Reading Difficulties in Adolescent Spanish-Speaking Language Minority Learners and Their Classmates

Michael J. Kieffer, EdD1

AbstractThis study investigated the role of morphological awareness weaknesses in the reading difficulties encountered by Spanish-speaking language minority learners and their native English-speaking peers in sixth grade. One hundred and thirty-eight students (82 language minority learners; 56 native English speakers) were assessed on English measures of reading comprehension, silent word reading fluency, and derivational morphological awareness. Students with specific reading comprehension difficulties, specific word reading difficulties, and combined difficulties were identified using categorical cut-scores. Findings indicated that morphological awareness differentiated skilled readers from students with reading difficulties. Substantial proportions of students with reading difficulties (38%–63%, depending on reading difficulty subtype) demonstrated weaknesses in morphological awareness. Language minority learners with reading difficulties were particularly likely to demonstrate weaknesses in morphological awareness (55%–64%), compared to native English speakers with similar reading difficulties (13%–50%). Findings suggest the diagnostic potential of morphological awareness for adolescent learners with reading difficulties, especially those from language minority backgrounds.

Keywordsreading difficulties, morphological awareness, language minority learners, English language learners, adolescence

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2 Journal of Learning Disabilities XX(X)

Cain, & Parrila, 2011). Yet it is unclear how prevalent such weaknesses are among students with reading difficulties. Moreover, it is unknown whether LM learners with reading difficulties are particularly likely to demonstrate weak-nesses in English MA, compared to their native English-speaking counterparts.

The current study was designed to shed light on the sources of reading difficulties in LM learners and their native English-speaking classmates by exploring the poten-tially important yet understudied domain of MA. Using data on linguistically diverse students in sixth grade, this study investigates the extent to which MA differentiates skilled readers from students with reading difficulties, the preva-lence of MA weaknesses among students with reading dif-ficulties, and the extent to which LM learners with reading difficulties are more likely to demonstrate MA weaknesses than their native English-speaking counterparts.

MA, Skilled Reading, and Reading Difficulties

As the other articles in this special issue demonstrate, grow-ing evidence supports the importance of MA to skilled read-ing and writing. During the earliest years of life, MA begins as an oral language skill, but in later years, as children learn to read and write, MA is developed through interaction with written text as well as oral language. Among various aspects of MA, derivational MA (i.e., awareness of the system by which affixes change words’ parts of speech or shades of meaning) may be particularly important for later stages of reading development for two reasons. First, the develop-mental course of derivational MA is longer than other aspects of MA, continuing into early adolescence (Kuo & Anderson, 2006), so it is likely to continue to demonstrate variation in older readers. Second, derived words are more frequent in the more sophisticated texts that older readers are expected to read (e.g., Nagy & Townsend, 2012).

There are at least three theoretical reasons that implicate MA in learning to read proficiently for both native English speakers and LM learners (Kuo & Anderson, 2006). First, morphemes have semantic, phonological, and orthographic properties, so awareness of these units requires integration of information from these linguistic systems in a way that mirrors many of the integrative processes involved in read-ing comprehension (Carlisle, 1995; Perfetti, Landi, & Oakhill, 2005). Second, the mental lexicons of skilled read-ers are organized morphologically (e.g., Nagy, Anderson, Schommer, Scott, & Stallman, 1989); children with better developed MA may have better organized mental lexicons and thus may have advantages in efficiently acquiring and storing morphologically complex vocabulary. Third, MA may help readers gain insight into the isomorphic principle of the English writing system—that is, that English mor-phemes retain their spelling despite shifts in sound accom-panying suffixation (e.g., popular and popularity). Each of

these reasons also provides support for the possibility that children with less developed MA will encounter difficulties with reading, to the extent that they are less skilled at inte-grating semantic, phonological, and orthographic informa-tion; that they have less well organized mental lexicons; and that they have less insight into the English writing system. All of these reasons apply to both native English speakers and LM learners learning to read in English.

Reading difficulties refer to students’ challenges in reaching grade-level expectations for extracting and con-structing meaning from written text (e.g., Snow et al., 1998). Although reading difficulties include neurologically based, genetically influenced reading disabilities, I use the term reading difficulties to include the wider range of chal-lenges with reading that have multifaceted causes including instructional influences, following Snow et al. (1998). Reading difficulties can be characterized as specific diffi-culties with word reading, specific difficulties with reading comprehension (in the presence of adequate word reading skills), or combined difficulties in word reading and reading comprehension (e.g., Gough & Tunmer, 1986).

Given the evidence cited above that MA makes unique contributions to both word reading and reading comprehen-sion, students with each of these profiles of reading difficul-ties are likely to demonstrate weaknesses in MA. Word reading difficulties may involve challenges in accurately and efficiently decoding the morphological information in morphologically complex words (e.g., Carlisle & Katz, 2006), whereas reading comprehension difficulties may involve challenges in extracting semantic and syntactic information from morphemes (e.g., Kieffer & Lesaux, 2008; Tong et al., 2011). Existing evidence from monolin-guals supports the general claim that students with reading difficulties have lower MA than skilled readers (e.g., Chu et al., 2006; Morris et al., 1998; Tong et al., 2011), but it is less clear how prevalent MA weaknesses are for each subtype of reading difficulties. It is further unclear whether LM learn-ers with reading difficulties demonstrate MA weaknesses at similar or higher rates, compared to their native English-speaking counterparts.

MA and Reading Development in LM Learners

Although the majority of research on derivational MA and reading has been conducted with monolingual learners, an emerging body of evidence suggests the importance of this skill for second-language learners (Deacon et al., 2007; Goodwin, Huggins, Carlo, August, & Calderon, in press; Kieffer et al., 2013; Kieffer & Lesaux, 2008, 2012a; Pasquarella et al., 2012; Ramirez et al., 2010). These studies have found that derivational MA uniquely predicts word reading and/or reading comprehension in LM learners, after controlling for important confounds including vocabulary, phonological awareness, and nonverbal ability.

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In particular, several studies conducted with Spanish-speaking LM learners in the upper elementary and middle school grades have found that derivational MA predicts English word reading and/or reading comprehension. For instance, Ramirez et al. (2010) found that derivational MA uniquely predicted English word reading in Grades 4 and 7. Goodwin et al. (in press) found that MA made a significant indirect contribution to reading comprehension via reading vocabulary in the upper elementary school grades. Likewise, Kieffer and Lesaux (2008) found that derivational MA uniquely predicted reading comprehension in Grade 5, a finding that Kieffer et al. (2013) replicated with a similar population in Grades 6 to 8. Similarly, Kieffer and Lesaux (2012a) found that derivational MA predicted both word reading fluency and reading comprehension among Spanish-speaking LM learners (as well as Filipino-speaking and Vietnamese-speaking LM learners) in Grade 6. Together, the existing evidence supports the role of MA in both word reading and reading comprehension develop-ment across the full range of individual differences, while raising questions about the extent and prevalence of MA weaknesses in students with difficulties.

MA and Reading Difficulties in LM Learners

Only a few studies have investigated the role of MA weak-nesses in reading difficulties with adolescent LM learners. Siegel (2008) explored whether children with dyslexia scored lower on derivational MA tasks than normally achieving readers in a sample of linguistically diverse stu-dents in Grade 6. Using a cut-score approach to identify students with dyslexia, she found that these learners scored significantly and substantially lower than normally achiev-ing students on both word and nonword derivational MA tasks. She also found no significant differences between LM learners and native English speakers in either the nor-mal achieving or the dyslexic groups, suggesting that LM learners with reading difficulties demonstrate MA weak-nesses, but at rates similar to those of native English speak-ers. Likewise, Lesaux and Kieffer (2010), in an investigation of reading comprehension difficulties among sixth graders, found that struggling LM readers and struggling native-English speaking readers performed at similarly low levels in derivational MA.

Given these findings, the question of whether MA is a par-ticularly common source of reading difficulties for LM learn-ers is an open one. On one hand, as a linguistic skill developed through both listening and reading, English derivational MA may be underdeveloped for learners who have had less expo-sure to English. Indeed, a couple of comparative studies have found that English MA is substantially lower among Spanish-speaking LM learners than among native English speakers (Kieffer & Lesaux, 2012a, 2012b). On the other hand, MA, as a metalinguistic skill, may be enhanced by exposure to two

languages (e.g., Bialystok, 2002), such that it could be a rela-tive strength for LM learners and less likely to be a source of reading difficulties for this population. In the absence of a sufficient body of comparative research, it is currently unknown whether MA weaknesses can explain some of the disproportionate reading difficulties encountered by LM learners. Investigating how common MA weaknesses are among linguistically diverse students with different subtypes of reading difficulties is important to informing identification and intervention efforts.

Current Study

This study was designed to investigate whether and to what extent students with reading difficulties from linguistically diverse backgrounds demonstrate weaknesses in deriva-tional MA in Grade 6. Two sets of research questions were addressed:

Research Question 1: (a) To what extent does deriva-tional MA differentiate students with reading difficul-ties (i.e., word reading difficulties, specific reading comprehension difficulties, or combined difficulties) from skilled readers? (b) To what extent do Spanish-speaking LM learners with reading difficulties demon-strate more severe weaknesses in MA compared to their native English-speaking counterparts with similar read-ing difficulties?Research Question 2: (a) What proportion of students with reading difficulties demonstrates weaknesses in derivational MA? (b) To what extent are Spanish-speaking LM learners with reading difficulties more likely to demonstrate weaknesses in derivational MA than their native English-speaking counterparts with similar reading difficulties?

Method

Participants

Participants included 138 students recruited from sixth-grade classrooms in two K-8 schools in Arizona. On sur-veys, 56 students reported speaking exclusively English at home and were classified as native English speakers, while 82 reported speaking Spanish to some extent at home and were classified as Spanish-speaking LM learners. This operational definition of language minority is consistent with that of the National Literacy Panel of Language Minority Children and Youth (August & Shanahan, 2006), as it includes students with limited English proficiency, stu-dents who are fully bilingual, and students who are domi-nant in the societal language when entering school. The term language minority learner should not be confused with the term English language learner (ELL), which refers

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4 Journal of Learning Disabilities XX(X)

to a subset of the LM learner population who lack sufficient English proficiency to benefit from mainstream English instruction without substantial support (August & Shanahan, 2006). Thirteen students were identified as ELLs based on school records, while the remaining LM learners were clas-sified as fluent English proficient.

Among the native English speakers, 46% self-identified as White, 26% as African American, 20% as Latino, 2% as Asian, 2% as Pacific Islander, and 5% as another group. Among the Spanish-speaking LM learners, 96% identified as Latino, 2% identified as White, and 1% identified as African American. Ninety-five percent of the LM learners had attended school in the United States since kindergarten, while the remaining 5% attended kindergarten in Mexico. The sample included 65 girls and 81 boys. The participating schools served students from mostly low-income back-grounds; one school reported approximately 81% of stu-dents as “economically disadvantaged” on their most recent school report card, whereas the other reported approxi-mately 65% of students as such. The absence of student-level data prevented me from determining if these percentages were similar for the LM learner and native English speaking subgroups. The language of instruction was exclusively English. As described in detail below, stu-dents with reading difficulties were identified based on their performance below the 25th percentile on national normed assessments of reading comprehension and/or word read-ing, following Siegel (2008) and others.

Measures

Reading comprehension. Comprehension of grade-level texts was assessed using the sixth-grade version of the reading comprehension subtest from the fourth edition of the Gates-MacGinitie Reading Test (MacGinitie, MacGinitie, Maria, & Dreyer, 2000). This norm-referenced measure provides stu-dents with 35 minutes to read several grade-level passages from expository and narrative texts and to complete multiple-choice questions. The publisher reports Kuder-Richardson Formula 20 reliability coefficients of .90 to .92 for the sixth-grade test, as well as extensive validity evidence.

Word reading fluency. Students’ ability to recognize printed words accurately and quickly was assessed using the Test of Silent Word Reading Fluency (Mather, Hammill, Allen, & Roberts, 2004). In this norm-referenced test, students are provided with rows of unrelated words of increasing diffi-culty with no spaces separating them (e.g., dimhowfigblue) and given 3 minutes to demarcate as many words as possible (e.g., dim|how|fig|blue). The publisher reports high estimates of reliability (i.e., test-retest reliability = .92; alternate-form reliability = .83) as well as validity evidence from several validation studies conducted by the authors. Independent peer-reviewed studies have provided additional validity evi-dence for this measure (Bell et al., 2006; Denton et al., 2011).

MA. Students’ awareness of derivational morphology was assessed using a nonword suffix choice task. This task was developed based on previous research with native English speakers (Nagy et al., 2006; Singson et al., 2000; Tyler & Nagy, 1989), while versions of this task have also been used with linguistically diverse samples (e.g., Kieffer & Lesaux, 2012b; Lesaux & Kieffer, 2010; Siegel, 2008). For each item on this 18-item task, students complete a sentence (e.g., The man is a great _______) by choosing a nonword with an appropriate derivational suffix (e.g., tranter) from among four choices (e.g., tranter, tranting, trantious, tranti-ful). To minimize the effects of decoding skills, the task was read aloud to students. The task had adequate reliability for the whole sample (Cronbach’s alpha = .78) and for the sub-samples of LM learners (Cronbach’s alpha = .77) and native English speakers (Cronbach’s alpha = .77). Several prior studies provide evidence for the validity of tasks using this paradigm, including evidence of convergent and divergent validity in native English-speaking (Nagy et al., 2006) and LM populations (Siegel, 2008) as well as evidence of con-struct validity based on confirmatory factor analytic models in both populations (Kieffer & Lesaux, 2012b).

Results

Descriptives

Table 1 provides sample means, standard deviations, and cor-relations for the measures of interest, with correlations disag-gregated by language background. As shown, the sample was performing in the low-average range on reading comprehen-sion and in the average range on word reading fluency.

Differences in MA by Reader Group

Following Siegel (2008), students were classified into reader groups, based on cut-scores—that is, the 25th percentile on the national norms for the reading comprehension and word reading fluency measure. Specifically, students were classi-fied as skilled readers, readers with specific weaknesses in

Table 1. Descriptive Statistics, With Sample Means and Standard Deviations, and Correlations for Language Minority Learners (n = 82) Above the Diagonal and Correlations for Native English Speakers (n = 56) Below the Diagonal.

M SD 1 2 3

1. Morphological awareness (raw score out of 18)

11.00 4.00 .58 .46

2. Reading comprehension (standard score)

94.57 13.40 .40 .41

3. Word reading fluency (standard score)

99.30 10.95 .42 .30

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Kieffer 5

word reading fluency (RD-Word; i.e., below the 25th percen-tile in word reading fluency, but above the 25th percentile in reading comprehension), readers with specific weaknesses in reading comprehension (RD-Comp; i.e., below the 25th per-centile in reading comprehension, but above the 25th percen-tile in word reading fluency), and readers with combined weaknesses in word reading fluency and reading comprehen-sion (RD-Word&Comp; i.e., below the 25th percentile in both reading comprehension and word reading fluency). Next, the means in z-scores on the MA task (based on the overall sample distribution) for each reader group and for each language group within each reader group were esti-mated and compared using t tests. Because differences in z scores are on a standard deviation scale (i.e., based on the whole-sample standard deviation), they can be interpreted as effect sizes in a manner analogous to interpreting Cohen’s d, where 0.20 is small, 0.50 is medium, and 0.80 is large. It is worth noting that, unlike Cohen’s d, differences in z scores are based on the standard deviation for the entire sample, rather than the pooled standard deviation for the two groups being compared. In the current study, differences in z scores are more appropriate than Cohen’s d because they are less likely to be influenced by outliers or idiosyncratic differences in variances between small groups.

Results indicated that overall (i.e., when not disaggre-gated by language group) readers with reading difficulties

of each type were substantially and statistically significantly lower in MA than skilled readers, as shown in Table 2. Specifically, all readers with reading difficulties performed nearly one whole-sample standard deviation below skilled readers in MA (difference in z scores = −0.92; t = −6.05; p < .001). Students in each of the three reading difficulty groups were also substantially and significantly below skilled readers in MA, including students in the RD-Comp group (difference in z scores = −0.72; t = −4.17; p < .001), students in the RD-Word group (difference in z scores = −0.91; t = −3.06; p = .003), and students in the RD-Word&Comp group (difference in z scores = −1.40; t = −6.32; p < .001). Students in the RD-Word&Comp group had the lowest MA among the reader groups, such that it was substantially and significantly lower than that of stu-dents in the RD-Comp group (difference in z scores = −0.68; t = −2.48; p = .016).

When disaggregated by language background, results suggest that LM learners with reading difficulties demon-strate more severe weaknesses in MA than their native English-speaking counterparts. Within the group of all readers with reading difficulties, the LM learners demon-strated substantially lower MA compared to that of native English speakers (difference in z scores = −0.77; t = −3.32; p = .003). Similarly, among students in the RD-Comp and RD-Word&Comp groups, LM learners demonstrated more

Table 2. Morphological Awareness z Scores by Reader and Language Subgroup (N = 138).

Mean

Difference With Skilled Readers (Positive Values

Favoring RD Group)

Difference Between LM and NE (Positive Values

Favor LM)

Skilled readers Overall (n = 76) 0.41 −0.23 LM (n = 42) 0.31 NE (n = 34) 0.54 All readers with reading difficulties (RD) Overall (n = 62) −0.51 −0.92*** −0.77** LM (n = 40) −0.78 −1.09*** NE (n = 22) −0.01 −0.55*Specific weaknesses in reading comprehension (RD-Comp) Overall (n = 37) −0.30 −0.72*** −0.90** LM (n = 22) −0.67 −0.98*** NE (n = 15) 0.23 −0.31Specific weaknesses in word reading fluency (RD-Word) Overall (n = 9) −0.50 −0.91** 0.34 LM (n = 4) −0.31 −0.62 NE (n = 5) −0.65 −1.19*Weaknesses in word reading & reading comprehension (RD-Word&Comp) Overall (n = 16) −0.98 −1.40*** −0.84 LM (n = 14) −1.09 −1.40*** NE (n = 2) −0.25 −0.80

Note. LM = language minority; NE = native English.*p < .05. p < .01. ***p < .001.

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6 Journal of Learning Disabilities XX(X)

severe weaknesses in MA compared to their native English-speaking counterparts in the same reading difficulty group; these differences were equally large for both groups, but only reached statistical significance for the RD-Comp group (for RD-Comp, difference in z scores = −0.90; t = −3.14; p = .003; for RD-Word&Comp, difference in z scores = −0.84; t = −1.43; p = .175). In contrast, among students in the RD-Word group, the LM learners demonstrated less severe weakenesses in MA than native English speakers, a difference that was not statistically significant (difference in z scores = 0.34; t = .40; p = .698). It is also worth pointing out that among skilled readers, the difference between LM learners and native English speakers was small and nonsig-nificant (difference in z scores = −0.23; t = 1.27; p = .209), suggesting that morphological weaknesses may be specific to LM learners with reading difficulties rather than a char-acteristic of the larger population of LM learners.

Prevalence of MA Weaknesses by Reader Group

The prevalence of MA weaknesses (defined as scoring below the 25th percentile for the sample) in each reader group and for each language group within each reader group was also estimated. When the prevalence of MA weak-nesses (defined as scoring below the 25th percentile in the sample distribution) by reader group and by language group was examined, such weaknesses were found to be more common among readers with reading difficulties and par-ticularly common among LM learners with reading difficul-ties, as shown in Table 3. Specifically, overall (when not disaggregated by language status), 45% of all readers with reading difficulties demonstrated weaknesses in MA, com-pared to 11% of skilled readers. When disaggregated by reading difficulty subtype, 38% of students in the RD-Comp group, 44% of students in the RD-Word group, and 63% of students in the RD-Word&Comp group demonstrated weaknesses in MA.

When disaggregated by language group, it becomes clear that high proportions of LM learners in each subgroup (50%–64%) demonstrated weaknesses in MA. Among all readers with reading difficulties, LM learners appeared to be more likely to demonstrate weaknesses compared to their native English-speaking counterparts, with 58% of LM readers with reading difficulties and only 23% of native English-speaking readers with reading difficulties demon-strating such weaknesses in MA. This difference appears to be driven by differences within the RD-Comp group, in which 55% of LM learners but only 13% of native English speakers demonstrated weaknesses in MA.

To provide insight into more severe MA weaknesses—that is, weaknesses such that students may not yet have insight into how derivational morphology works—the pro-portion of each group that scored below the chance level (i.e., scoring below 25% correct or 4 or fewer items out of

18 correct) on the multiple-choice MA task was also esti-mated, as shown in the rightmost column in Table 3. Overall, 16% of readers with reading difficulties scored below the chance level, with proportions between 11% and 25% by reading difficulty subtype, compared to 0% of skilled read-ers. Within the RD-Comp and RD-Word&Comp subgroups, these proportions were notable for LM learners (18% to 29%), whereas no native English speakers in these sub-groups scored below the chance level. It is worth noting that this is a stringent criterion for chance. When a less stringent criterion is used, such as including cases within the 95% confidence interval for chance, the cut-score for MA weak-nesses is the same as the 25th sample percentile, so the pro-portions reporting in the third column of Table 3 can also be interpreted as the proportions of students scoring below the chance level using a less stringent criteria for chance.

Discussion

This study was designed to investigate the extent to which derivational MA differentiates students with reading diffi-culties from skilled readers and to estimate the proportion of students with reading difficulties who demonstrate MA weaknesses. In addition, the study aimed to examine whether Spanish-speaking LM learners with reading diffi-culties were more likely to demonstrate weaknesses in English MA than their native English-speaking counterparts with similar difficulties. Findings indicated that MA differ-entiated readers with reading difficulties from skilled read-ers. Overall, 45% of readers with reading difficulties demonstrated weaknesses in MA and substantial propor-tions (between 38% and 63%) of each reading difficulty subtype demonstrated weaknesses in MA. There was also evidence that LM learners with reading difficulties were more likely to demonstrate weaknesses in MA, with 58% of LM learners with reading difficulties demonstrating MA weaknesses, compared to 23% of native English speakers with reading difficulties. In addition, a notable proportion (20%) of LM learners with reading difficulties demon-strated severe weaknesses in MA, such that they performed below chance on the multiple-choice MA measure. These findings have important implications for understanding the reading difficulties of LM learners.

MA as a Common Source of Reading Difficulties for LM Learners

The current findings indicate that derivational MA should be taken seriously as a potential source of reading difficulties for adolescent LM learners. The findings converge with evi-dence that Spanish-speaking LM learners demonstrate lower levels of derivational MA in English than native English speakers (e.g., Kieffer & Lesaux, 2012a, 2012b), while clari-fying that these differences are substantial among readers

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Kieffer 7

with reading difficulties, but may be negligible among skilled readers. If MA weaknesses are not common among LM learners in general, but are rather specific to LM learn-ers with reading difficulties, this has valuable implications for identifying students for intervention. For instance, teach-ing morphology in the middle school grades may be more effective as a Tier 2 intervention for students with reading difficulties, rather than as Tier 1 instruction for all students, under a multitiered Response to Intervention framework (Fuchs & Fuchs, 2006). Additional research is certainly needed to evaluate this possibility, but it seems reasonable that morphology instruction will be most effective for those students who struggle with the morphological tasks neces-sary for reading and comprehending grade-level texts.

At the same time, the findings diverge from two prior studies (Lesaux & Kieffer, 2010; Siegel, 2008) that have found no differences in derivational MA between LM learn-ers and native English speakers who similarly struggle with reading. These divergences are particularly striking, in that the current study and these two prior studies all examined Grade 6 students and used similar nonword MA measures. The divergence with Siegel (2008) may be due to other dif-ferences in poverty levels or other characteristics of the populations and educational contexts studied, because her study was conducted with immigrant children in Canada who tended to be middle-class and had received high-qual-ity early language and literacy instruction. The divergence with Lesaux and Kieffer (2010) may be due to differences in the cut-scores used (their study used the 35th percentile to identify struggling comprehenders) or language back-grounds (their LM learners were predominately but not

exclusively Spanish-speaking). Given the small number of studies on this question, these divergences may also be due simply to sampling error, raising the need for further repli-cation of these findings.

The current findings also shed light on the role of MA in specific types of reading difficulties. In particular, the find-ings indicated that MA weaknesses were most severe and common among students with difficulties in both word reading and comprehension (63% of these readers demon-strated MA weaknesses). Because MA plays roles in both word reading and reading comprehension, it makes sense that weaknesses in MA may play out as weaknesses in both domains. Readers who have combined difficulties in both word reading and reading comprehension in early adoles-cence may be particularly challenging to serve, given their multiple challenges and the time pressure of middle school settings, but the current findings suggest that MA may be a promising avenue for intervention.

The role of MA in combined reading difficulties may be particularly important given the relatively high prevalence of these difficulties among LM learners in this sample. Seventeen percent of LM learners in the sample demon-strated combined weaknesses compared to only 4% of native English speakers, which is somewhat surprising in light of evidence that LM learners generally perform at similar lev-els to native English speakers on word reading accuracy (Lesaux, Koda, Siegel, & Shanahan, 2006). In contrast to this finding, Lesaux and Kieffer (2010) found that 12% of linguistically diverse sixth graders demonstrated combined weaknesses in word reading accuracy and comprehension, but found no evidence that this profile was particularly

Table 3. Prevalence of Weaknesses in Morphological Awareness by Reader and Language Subgroup (N = 138).

Reader Group Language Group

Percent (Number) Scoring Below the Sample 25th Percentile Rank/Below 95% Confidence Interval

for Chance

Percent (Number) Scoring Below 25% Chance Using a

Stringent Criterion

Skilled readers Overall (n = 76) 11% (8) 0% (0)LM (n = 42) 12% (5) 0% (0)NE (n = 34) 9% (3) 0% (0)

All readers with reading difficulties (RD)

Overall (n = 62) 45% (28) 16% (10)LM (n = 40) 58% (23) 20% (8)NE (n = 22) 23% (5) 9% (2)

Specific weaknesses in reading comprehension (RD-Comp)

Overall (n = 37) 38% (14) 11% (4)LM (n = 22) 55% (12) 18% (4)NE (n = 15) 13% (2) 0% (0)

Specific weaknesses in word reading fluency (RD-Word)

Overall (n = 9) 44% (4) 22% (2)LM (n = 4) 50% (2) 0% (0)NE (n = 5) 40% (2) 40% (2)

Weaknesses in word reading & reading comprehension (RD-Word&Comp)

Overall (n = 16) 63% (10) 25% (4)LM (n = 14) 64% (9) 29% (4)NE (n = 2) 50% (1) 0% (0)

Note. LM = language minority; NE = native English.

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8 Journal of Learning Disabilities XX(X)

common for LM learners. This divergence could be due to differences in the educational contexts studied (e.g., their efficacy in teaching word reading to LM learners), but may also be related to the use of a word reading fluency measure rather than an accuracy measure; reading fluency involves the coordination of multiple skills (Berninger, Abbott, Billingsley, & Nagy, 2001), including English language skills that may be underdeveloped in LM learners.

MA also differentiated readers with specific comprehen-sion difficulties from skilled readers. For LM learners in particular, MA weaknesses were demonstrated by a major-ity of students with specific comprehension difficulties (55%). The sources of specific comprehension difficulties are less well-understood than word reading difficulties (e.g., Cain & Oakhill, 2006), so this finding suggests that MA weaknesses may be central to some of these difficul-ties. Together, these findings suggest that derivational MA needs to be considered in future research to understand both word reading and comprehension difficulties.

Incorporating MA Into a Model of Reading DifficultiesTheoretical models of reading development have rarely addressed morphology, while theories of reading difficul-ties have focused on phonologically based weaknesses (e.g., Ziegler & Goswami, 2005). For instance, the widely influential Simple View of Reading (Gough & Tunmer, 1986) posits that skilled reading is the product of decod-ing and linguistic comprehension, with the corollary that reading difficulties are characterized by weaknesses in one or both of these two broad domains. Although helpful in distinguishing between different types of reading dif-ficulties, the Simple View does not specify which compo-nent skills are important to skilled linguistic comprehension and thus provides insufficient guidance to diagnosing and intervening for linguistic comprehension-based reading difficulties.

The current findings support the inclusion of MA, among a range of other linguistic skills, in the broad domain of linguistic comprehension that is required for successful reading as suggested by Tong et al. (2011) among others. At the same time, to the extent that students with combined word reading and reading comprehension difficulties dem-onstrated the highest prevalence of MA weaknesses, the current findings also support the consideration of MA in the domain of decoding.

The current results are also relevant to the refinement of the lexical quality hypothesis (Perfetti, 2007; Perfetti & Hart, 2001). According to Perfetti (2007), lexical quality refers to “the extent to which the reader’s knowledge of a given word represents the word’s form and meaning con-stituents and knowledge of word use that combines mean-ing with pragmatic features” (p. 359). Given that morphemes

have phonological, orthographic, and semantic properties, awareness of these units is likely to be central to lexical quality. The lexical quality hypothesis further states that variation in the quality of word representations has conse-quences for reading comprehension. The MA weaknesses demonstrated by the readers with reading difficulties in the present study may point to core weaknesses in lexical quality.

By providing correlational evidence for the extent to which MA differentiates students with reading difficulties from skilled readers, the current findings support the hypothesis that students with underdeveloped insight into the morphological system are ill-equipped both to decode morphologically complex words accurately and efficiently and to extract meaning from texts that includes such words. One practical implication is that educators should assess readers with reading difficulties in MA to determine if weaknesses in this specific linguistic skill may be a poten-tial source of their difficulties.

In addition, the current findings suggest that MA may be a particularly important skill to consider for LM learners with reading difficulties. As a linguistic skill developed through interaction with both oral and written texts, MA in English may be especially underdeveloped in readers who have had less exposure to the English language. In contrast to phonological awareness, which tends to develop simi-larly and to similar levels in LM learners and native English speakers (e.g., Lesaux et al., 2006), MA may offer one par-tial explanation for the disproportionate reading difficulties encountered by LM learners. Although much more research is needed to support the causal claim that MA weaknesses cause some or many LM learners’ reading difficulties, evi-dence from this study and others suggest that this is a prom-ising hypothesis.

At the same time, given the high correlation between MA and vocabulary knowledge (e.g., Kuo & Anderson, 2006), it is likely that the MA weaknesses demonstrated by the students with reading difficulties are combined with vocabulary weaknesses. Our findings demonstrate that MA weaknesses are common among students with reading dif-ficulties, but do not establish the extent to which their weak-nesses are specific to MA, as opposed to indicating more general weaknesses in language comprehension skills. Relatedly, our findings suggest the diagnostic potential of MA tasks, but do not tell us whether they are more informa-tive than vocabulary tasks. Given evidence for vocabulary weaknesses among struggling reading, particularly LM struggling readers (e.g., Lesaux & Kieffer, 2010), there is good reason to include both MA and vocabulary measures into diagnostic batteries. Future research is necessary to determine how combining vocabulary and MA tasks can provide the most useful diagnostic information for under-standing the sources of reading difficulties for linguistically diverse learners.

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Kieffer 9

Limitations and Future Research

The current study has some limitations to be addressed in future research. First, its correlational design prevents causal conclusions about the sources of reading difficulties. Second, the operational definition of MA weaknesses was sample-specific, in that it was based on low performance relative to the sample distribution, rather than a norming distribution. Although a reasonable approach in the absence of norm-referenced measures of MA, this may have under-estimated the prevalence of MA weaknesses if this largely low-income sample performed lower in MA than would have a nationally representative sample. Third, student-level data on socioeconomic status were not available, so it is unclear to what extent the differences between LM learn-ers and native English speakers found was related to differ-ences in socioeconomic status. Fourth, although the MA measure had good evidence of validity from prior research, it would have been beneficial to include additional MA measures, perhaps including measures of root awareness as well as suffix awareness, to determine if findings generalize across different measurement approaches. Fifth, although the overall sample size was adequate, the subgroups of LM learners and native English speakers with each subtype of reading difficulty were relatively small, limiting statistical power to detect small differences.

Conclusions

This study investigated the existence and prevalence of MA weaknesses among linguistically diverse students with read-ing difficulties. Findings indicated that MA weaknesses were common across different types of reading difficulties and were disproportionately common for LM learners with reading difficulties, compared with their native English-speaking counterparts with similar difficulties. This suggests the diagnostic potential for assessing MA among readers with reading difficulties, especially for LM learners.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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