Heidi Waterfall

Sources of Variability in Children’s Language Growth

The present longitudinal study examines the role of caregiver speech in language development, especially syntactic development, using 47 parent-child pairs of diverse SES background from 14 to 46 months. We assess the diversity (variety) of words and syntactic structures produced by caregivers and children. We use lagged correlations to examine language growth and its relation to caregiver speech. Results show substantial individual differences among children, and indicate that diversity of earlier caregiver speech significantly predicts corresponding diversity in later child speech. For vocabulary, earlier child speech also predicts later caregiver speech, suggesting mutual influence. However, for syntax, earlier child speech does not significantly predict later caregiver speech, suggesting a causal flow from caregiver to child. Finally, demographic factors, notably SES, are related to language growth, and are, at least partially, mediated by differences in caregiver speech, showing the pervasive influence of caregiver speech on language growth.

The varieties of speech to young children.

This article examines caregiver speech to young children. The authors obtained several measures of the speech used to children during early language development (14-30 months). For all measures, they found substantial variation across individuals and subgroups. Speech patterns vary with caregiver education, and the differences are maintained over time. While there are distinct levels of complexity for different caregivers, there is a common pattern of increase across age within the range that characterizes each educational group. Thus, caregiver speech exhibits both long-standing patterns of linguistic behavior and adjustment for the interlocutor. This information about the variability of speech by individual caregivers provides a framework for systematic study of the role of input in language acquisition.

Emergence of Syntax: Commonalities and Differences across Children.

This paper presents the results of a longitudinal examination of syntactic skills, starting at the age of emergence of simple sentences and continuing through the emergence of complex sentences. We ask whether there is systematic variability among children from different socioeconomic backgrounds in the early stages of sentence production. The results suggest a different answer for simple versus complex sentences. We found a striking similarity across SES groups on the measures tapping early mastery of basic syntactic rules of simple sentences. At the same time, there was a significant difference between SES groups in the mastery of complex sentence structures. This difference emerged at the earliest stages of production of multi-clause sentences and persisted throughout the period of observation. The implications of these findings for the understanding of mechanisms of syntactic development are discussed.

Effects of Language Intervention on Syntactic Skill Levels in Preschoolers.

Questions concerning the role of input in the growth of syntactic skills have generated substantial debate within psychology and linguistics. The authors address these questions by investigating the effects of experimentally manipulated input on childrens skill with the passive voice. The study involved 72 four-year-olds who listened to stories containing either a high proportion of passive voice sentences or a high proportion of active voice sentences. Following 10 story sessions, childrens production and comprehension of passives were assessed. Intervention type affected performance--children who heard stories with passive sentences produced more passive constructions (and with fewer mistakes) and showed higher comprehension scores than children who heard stories with active sentences. Theoretical implications of these results for the understanding of the nature of syntactic skills and practical implications for the development of preschool materials are discussed.

Learn locally, act globally: learning language from variation set cues.

Variation set structure--partial overlap of successive utterances in child-directed speech--has been shown to correlate with progress in childrens acquisition of syntax. We demonstrate the benefits of variation set structure directly: in miniature artificial languages, arranging a certain proportion of utterances in a training corpus in variation sets facilitated word and phrase constituent learning in adults. Our findings have implications for understanding the mechanisms of L1 acquisition by children, and for the development of more efficient algorithms for automatic language acquisition, as well as better methods for L2 instruction.

General cognitive principles for learning structure in time and space

How are hierarchically structured sequences of objects, events or actions learned from experience and represented in the brain? When several streams of regularities present themselves, which will be learned and which ignored? Can statistical regularities take effect on their own, or are additional factors such as behavioral outcomes expected to influence statistical learning? Answers to these questions are starting to emerge through a convergence of findings from naturalistic observations, behavioral experiments, neurobiological studies, and computational analyses and simulations. We propose that a small set of principles are at work in every situation that involves learning of structure from patterns of experience and outline a general framework that accounts for such learning.

An empirical generative framework for computational modeling of language acquisition

This paper reports progress in developing a computer model of language acquisition in the form of (1) a generative grammar that is (2) algorithmically learnable from realistic corpus data, (3) viable in its large-scale quantitative performance and (4) psychologically real. First, we describe new algorithmic methods for unsupervised learning of generative grammars from raw CHILDES data and give an account of the generative performance of the acquired grammars. Next, we summarize findings from recent longitudinal and experimental work that suggests how certain statistically prominent structural properties of child-directed speech may facilitate language acquisition. We then present a series of new analyses of CHILDES data indicating that the desired properties are indeed present in realistic child-directed speech corpora. Finally, we suggest how our computational results, behavioral findings, and corpus-based insights can be integrated into a next-generation model aimed at meeting the four requirements of our modeling framework.

Cross-linguistic syntactic priming in bilingual children

Previous research has used cross-linguistic priming methodology with bilingual adults to explore the nature of their syntactic representations. The present paper extends the use of this methodology to bilingual children to investigate the relation between the syntactic structures of their two languages. Specifically, we examined whether the use of passives by the experimenter in one language primed the subsequent use of passives by the child in the other language. Results showed evidence of syntactic priming from Spanish to English: hearing a Spanish sentence containing a passive led to the increase in childrens production of the parallel structure in English. However, there was no priming in the other direction: hearing an English sentence containing a passive did not increase childrens use of the parallel structure in Spanish. These results provide evidence for both the integration of syntactic representations in bilingual children and the asymmetry of the relation between their two languages.

Beyond Syntactic Priming: Evidence for Activation of Alternative Syntactic Structures.

Priming methodology was previously used to investigate childrens ability to represent abstract syntactic forms. Existing evidence indicates that following exposure to a particular syntactic structure (such as the passive voice), English-speaking children increase their production of that structure with new lexical items. In the present work, we utilize priming methodology to explore whether exposure to passive primes may increase childrens production of sentences that have a different structure but share a similar purpose in discourse. We report three studies, two involving English- and Russian-speaking children, and a third involving Russian-speaking adults. Unlike English, Russian offers a variety of syntactic forms that emphasize the patient of a transitive action, thus fulfilling the discourse function of the passive. We found that English speakers increased the use of the particular syntactic form presented in the prime, whereas Russian speakers increased their production of several different syntactic forms used to emphasize the patient of the action.

Priming a perspective in Spanish monolingual children: the use of syntactic alternatives.

We used a syntactic priming paradigm to show priming effects for active and passive forms in monolingual Spanish-speaking four- and five-year-olds. In a baseline experiment, we examined childrens use of the fue-passive form and found it was virtually non-existent in their speech, although they produced important elements of the form. Children used a more frequent Spanish passive form, the subjectless/se-passive. In a priming experiment, we presented children with drawings described using either active or fue-passive sentences. Children then described novel drawings. Priming was induced for active and passive forms; however, children did not produce the fue-passive provided for them. Instead, children used the subjectless/se-passive and what we term the function-passive, which like the fue-passive, emphasize the patient of the action. We argue that childrens use of different passive forms suggests they are sensitive to experimenters input as it relates to scene interpretation and to syntax.