Are some parents' interaction styles associated with richer grammatical input?

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.