This manuscript-based dissertation is comprised of three interrelated longitudinal studies on Spanish language growth and deceleration and its impact on English language growth and English reading skills in bilingual children. Chapter 1 introduces the manuscript-based dissertation and provides the background on existing, longitudinal work of dual Spanish-English language growth and Spanish deceleration. It describes the theoretical framework of dynamical systems model and cross-linguistic relations hypotheses as applied to the three studies, which characterize the complexity of dual language growth trajectories over time. Chapter 1 also introduces core methodological aspects shared across the studies, such as the overall sample of participants, the longitudinal language sampling protocol, and the primary oral language measures used for analysis. Finally, it details the specialized analytic approach used for each of the three longitudinal studies, growth curve modeling (GCM). Chapter 2 (Study 1) provides a more detailed review of prior literature on Spanish and heritage language deceleration, as well as their possible limitations. This study has been completed, submitted for publication, and is under revision. It aimed to determine if Spanish deceleration or growth was found in two grammatical (mean length of utterance in words and proportion of grammatical utterances) and two lexical (number of different words and moving-average type token ratio) measures in subgroups of participants academically instructed in English. The results indicate that subgroups of participants demonstrated either Spanish growth or deceleration on the grammatical and lexical measures. Chapter 3 (Study 2) discusses different academic settings and language of instruction for Spanish-English bilinguals, as well as opposing views and different outcomes based on language of instruction. This study aimed to determine if there are differences in the oral language development in Spanish and English for bilingual children in either English or Spanish instruction. It also examines the potential impact of language of instruction on Spanish and English language growth or deceleration using one grammatical measure (proportion of grammatical utterances) and one lexical measure (moving-average type-token ratio). Results indicate that bilingual children differed in their rates of Spanish and English oral language development as a function of their primary language of instruction in school. The children who received Spanish instruction in school had faster rates of growth in Spanish and English. The children who received English instruction demonstrated significant deceleration of their Spanish grammatical skills. Chapter 4 (Study 3) examines the longitudinal impact of Spanish oral language skills on English language and reading skills. Academic performance and standardized testing of bilinguals, and prior longitudinal studies of oral language on reading skills are reviewed. The primary aim of this study was to systematically determine how early Spanish language (growth or deceleration) may impact later English oral language and reading skills. The results detail the estimated growth and potential deceleration of two Spanish oral language measures (proportion of grammatical utterances, moving-average type-token ratio), and the impact of Spanish language measures on the same English oral language measures and one English reading measure (Measure of Academic Progress – Reading). Neither Spanish grammatical nor lexical productive skills were found to impact growth of English language or reading skills. Overall growth was found for all measures with the exception of a subgroup of participants who experienced deceleration of Spanish grammatical skills. Chapter 5 draws general conclusions and possible clinical implications from the results obtained from the three dissertation studies. Although the studies overall encompass relatively small sample sizes (N = 34 Study 1; N = 90 Study 2; N = 57 Study 3), they were larger and spanned a longer time course than the majority of prior longitudinal studies focused on Spanish deceleration. The low socioeconomic household status of the participants also makes them more representative of Hispanic Spanish-English bilinguals in the U.S. Future planned studies beyond this series include a qualitative analysis of possible markers of Spanish deceleration.

Prominent researchers from the US, Mexico, Chile, Colombia and Spain contribute experimental reports on language development of children who are acquiring Spanish. The chapters cover a wide range of dimensions in acquisition: comprehension and production; monolingualism and bilingualism; typical development, children who are at risk and children with language disorders, phonology, semantics, and morphosyntax. These studies will inform linguistic theory development in clinical linguistics as well as offer insights on how language works in relation to cognitive functions that are associated with when children understand or use language. The unique data from child language offer perspectives that cannot be drawn from adult language. The first part is dedicated to the acquisition of Spanish as a first or second language by typically-developing children, the second part offers studies on children who are at risk of language delays, and the third part focuses on children with specific language impairment, disorders and syndromes.

Communication Sciences

In this dissertation I investigate how community context affects Spanish language use and English proficiency among Latina and Latino children in the United States, focusing on the children of immigrants. I view children's language attributes through a sociological perspective that recognizes that children learn and use languages within specific social and cultural contexts, and that these contexts have an important effect on language acquisition and use. This theoretical perspective leads to the hypothesis that children's language skills and language use will be affected by the communities they live in. I predict that living in a metropolitan area with a greater propinquity and availability of Spanish speakers will increase a child's likelihood of speaking Spanish, because this will increase opportunities for using and hearing Spanish and promote Spanish within a larger United States context that often devalues languages other than English. At the same time, I hypothesize that community context will have little effect on children's English skills because of the ubiquitous presence of English in the daily life of any U.S. child. I test these hypotheses using a national sample of children who live in metropolitan areas drawn from the 1990 Census. I find that levels of Spanish maintenance are extremely high among children of Latina/o immigrants, and that a large majority of children who are born in the U.S. speak English fluently. Multivariate analysis demonstrates that several dimensions of a metropolitan area's language context-in particular the saturation and segregation of Spanish speakers-have a strong effect on second-generation children's likelihood of speaking Spanish that persists even after controlling for household- and individual-level variables. Contrary to my original hypothesis, I also find that the language characteristics of the metropolitan area have a significant effect on children's English proficiency. This effect, however, is smaller than the effect of metropolitan context on Spanish use. This analysis produces a better understanding of the specific elements of household and community context that affect language use. The results imply that children of immigrants are following multiple paths to language adaptation, and that metropolitan context is an important influence on this process of adaptation.

Four studies explored patterns of language growth and processing in 64 19-31-month-old bilingual children acquiring English and Spanish. In the first study, cross-sectional and longitudinal methods revealed significant relationships between vocabulary size and grammatical development, replicating previous studies with monolingual children. The compositions of children's lexicons in each language were linked to vocabulary size in that language. With few exceptions, utterance length and complexity and the emergence of closed class and predicate terms in each language were linked more closely to vocabulary size in the same language than to total conceptual vocabulary (TCV) size. In the second study, performance on English and Spanish sentence repetition tests was compared for bilingual and monolingual children matched for vocabulary size in each language. The performance of the bilingual children was similar to that of their monolingual controls, indicating links between grammatical ability and vocabulary development within the same language. The slightly better performance of the bilingual children on a few comparisons suggested some degree of cross-linguistic bootstrapping. In the third study, event-related potentials (ERPs) were used to investigate the neural activity of bilingual children as they processed known and unknown words. There were differences in the timing and distribution of the ERP amplitude differences to known vs. unknown words for each language, and differences in these effects when children with larger TCV sizes were compared to those with smaller TCV sizes. These results thus replicated studies with monolingual children that found links between vocabulary development and the organization of ERP effects, although the exact patterns were different for the bilingual and monolingual children. In the fourth study the effects of mixed vs. blocked language testing conditions on ERP patterns were investigated. Results indicated that some of the differences in ERP effects between the monolingual and bilingual children noted in the third study may have been due to processing demands created by the mixed-language testing condition in which the bilingual children were tested. The results of these four studies support experience-based accounts of early language acquisition, and further establish the use of combined behavioral-neural imaging approaches for studying language development in bilingual toddlers.

This dissertation explores the literacy abilities of Spanish-speaking bilingual children who are taught in English. They are a growing demographic, accounting for 9% of total enrollment in U.S. schools and 20% of enrollment in California. Their reading difficulties begin in pre-school and appear to persist throughout their academic careers. Literacy acquisition is crucial for both academic and career success. Bilingual children present an opportunity to study reading acquisition in a typically-developing child who comes from a non-monolingual language environment. In addition, this information can help guide educational policy to provide help where it is needed most. In order to identify areas of need, it is instructive to compare the bilingual children to their monolingual peers. These groups are compared not to belabor differences between them but to uncover areas that seem most vulnerable in the bilingual children. The monolingual children serve as a necessary reference point to gauge relative strengths and weaknesses in the bilingual children. Chapter 1 presents an overview of how reading and written expression develop in monolingual children, and how demographic and within- and cross-language factors affect this development. In Chapter 2, demographic and English language factors are explored in a cohort of 67 monolingual and 65 SEB bilingual from first through fourth grades. Chapter 3 is an examination of the impact of words that share form and meaning (i.e., train/tren) or form but not meaning (i.e., pan/pan, which means bread) cross-linguistically on single-word processing in the same cohort. Chapter 4 provides a detailed analysis of the written narrative abilities of a larger cohort of monolingual and bilingual children. In Chapter 5, implications of the results and future directions are discussed. This dissertation presents a comprehensive exploration of the reading and written expression abilities of bilingual children. The results suggest that demographic variables may be more important than linguistic ones in explaining the reading challenges in the bilingual group. They also serve to highlight areas of particular need in the linguistic profile of the bilingual children.