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Purpose: Evidence for tense marking in child-directed speech varies both across languages (Guasti, 2002; Legate & Yang, 2007) and across speakers of a single language (Hadley, Rispoli, Fitzgerald, & Bahnsen, 2011). The purpose of this study was to understand how parent interaction styles and register use overlap with the tense-marking properties of child-directed speech. This study investigated how parent interaction style, measured by utterance function, and parent register use when asking questions interacted with verb forms in child-directed input to identify interaction styles associated with the richest grammatical input. Method: Participants were 15 parent-toddler dyads. The communicative function of parent utterances and the form of their questions were coded from language samples of parent-child play when children were 21 months of age. Verbs were coded for linguistic form (e.g., imperative, modal, copula). Results: Directives and reduced questions were both negatively related to input informativeness (i.e., the proportion of unambiguous evidence for tense). Other-focused descriptives were positively related to input informativeness. Conclusion: Predictable overlap existed between the characteristics of parents' interaction styles and register use and their input informativeness. An other-focused descriptive style most strongly related to richer evidence for the +Tense grammar of English. [ABSTRACT FROM AUTHOR]

Purpose: The relatedness of tense morphemes in the language of children younger than 3 years of age is a matter of controversy. Generativist accounts predict that the morphemes will be related, whereas usage-based accounts predict the absence of relationships. This study focused on the increasing productivity of the 5 morphemes in the tense productivity score (copula BE, third-person singular present -3s, past -ed, auxiliary DO, auxiliary BE; Hadley & Short, 2005) and their relationship to one another. Method: Twenty typically developing children were observed longitudinally from 21 to 33 months of age. One hour of naturalistic caregiver-child interaction sampled every 3 months was analyzed. Results: Copula BE was more productive than all other morphemes from age 27 months onward. Auxiliary BE was significantly less productive than -3s, -ed, and DO from age 27 months onward. Evaluation of third-person singular tense morphemes at age 33 months revealed that the productivity scores of copula is, -3s, and does were all correlated. Conclusions: There is sequence and simultaneity in development that no prior framework has fully explained, as well as evidence of cross-morpheme relationships. In this article, the authors interpret these findings as support for the gradual morphosyntactic learning hypothesis (Rispoli & Hadley, 2011; Rispoli, Hadley, & Holt, 2009). [ABSTRACT FROM AUTHOR]

Purpose: Theories of morphosyntactic development must account for between-child differences in morphosyntactic growth rates. This study extends Legate and Yang's (2007) theoretically motivated crosslinguistic approach to determine if variation in properties of parent input accounts for differences in the growth of tense productivity. Method: Fifteen toddlers (and parents) participated. None were producing tense morphemes productively at 21 months. Two dependent measures of morphosyntactic growth between 21 and 30 months were used: empirical Bayes linear coefficients at 21 months and predicted productivity scores at 30 months. Predictor variables included child sex, vocabulary, and mean length of utterance as well as 4 measures of parent language input at 21 months. Results: Input informativeness for tense was the most consistent predictor of morphosyntactic growth, explaining 28.3% of the unique variance in children's linear growth coefficients at 21 months and 23.0% of the unique variance in predicted tense productivity scores at 30 months. General input measures were unrelated. Child sex explained an additional 24.7% of the variance in early linear growth. Child vocabulary at 21 months did not explain a significant proportion of unique variance. Conclusion: The findings provide evidence that input informativeness, an abstract and distributed property of input, contributes to morphosyntactic growth. [ABSTRACT FROM AUTHOR]