The power of the page: Comparing richness in text and talk during book sharing with two-year-old children

Sharing books with young children has long been associated with positive outcomes for children’s language and literacy outcomes. Studies suggest that caregiver language during these book-sharing interactions is linguistically richer than speech directed to young children (target-child-directed speech; tCDS) during other everyday activities. However, few studies have directly compared the linguistic richness of speech in book sharing and other activities within the same families. In this study, tCDS was sampled from day-long naturalistic recordings to investigate the linguistic richness of speech directed to 24-month-old children from English- and Spanish-speaking families in the U.S. We compared four sources of speech: book text, read-aloud speech during book-sharing interactions, spontaneous speech during book-sharing interactions, and spontaneous speech during other everyday activities. We first used a mega-transcript approach combining across families (Dawson et al., 2021; Montag et al., 2015) and compared the four sources of language on type-token ratio curves. We next conducted a more fine-grained analysis to look within families, comparing the four sources of speech in terms of lexical (lexical diversity, lexical density, lexical frequency, and contextual diversity) and grammatical (mean length of utterance in words and the proportion of complex utterances) measures associated with linguistic richness. Across both approaches and in both language groups, speech based on text was lexically and grammatically richer than both sources of spontaneous speech. These results indicate that the power of the proposed linguistic richness of speech during book-sharing interactions stems from features of the text on the page.