Mothers used wider vocabulary and talked to their six-month-old infants more during shared book reading than when they played with toys

Aim: We compared mothers reading books to six-month-old infants or playing with toys and measured whether the maternal language input influenced the children's spoken vocabulary at 18 months of age. Method: This Taiwanese study recruited 46 dyads and video recorded them while the mothers read books to their infants and played with them with toys at 6 months of age. The mothers' lexical diversity, which is the ratio of different unique words to the total number of words, was measured. We then assessed the children's spoken vocabulary at 18 months. Results: The mother used more diverse vocabulary and a higher number of words when they were reading books than playing with toys with their children (p = 0.001). Maternal lexical diversity at 6 months of age accounted for 14.4% of the unique variance in the number of different words used by the child at 18 months. We believe that this is a novel finding. Conclusion: Mothers used wider vocabulary and talked to their infants more during book reading than when they played with toys. Diverse maternal vocabulary at 6 months of age positively influenced the number of different words their children used at 18 months of age.