Children acquiring Japanese differ from those acquiring English with regard to the rate at which verbs are learned (Fernald & Morikawa, 1993). One possible explanation is that Japanese caregivers use verbs in referentially transparent contexts, which facilitate the form-meaning link. We examined this hypothesis by assessing differences in verb usage by Japanese and American caregivers during dyadic play with their infants (5-22 months). We annotated verb-containing utterances for elements associated with referential transparency and compared across groups. Contrary to our hypotheses, we found that Japanese caregivers used verbs in fewer referentially transparent contexts than American caregivers, or did not significantly differ from American caregivers, depending on the measure. These findings cast doubt on cross-cultural differences in referential transparency between Japanese and American child-directed input.

This study examined early Hebrew verb acquisition, highlighting CDS–CS relations across inflectional and derivational verb learning. It was carried out on a corpus of longitudinal dense dyadic interactions of two Hebrew-speaking toddlers aged 1;8–2;2 and their parents. Findings revealed correlated patterns within and between CDS and CS corpora in terms of verbs, structural root categories, and their components (roots, binyan conjugations, and derivational verb families), and clear relations between lexical-derivational development and inflectional growth in input–output relations, measured by MSP. It also showed that both corpora had few, yet highly semantically coherent, derivational families. Lexical learning in Hebrew was shown to be morphologically oriented, with both inflectional and derivational learning supporting and being supported by the development of the verb lexicon. These findings support findings in the general literature regarding the close relationship between parental input and child speech, and the affinity between lexical and grammatical growth.