Happy babies, chatty toddlers: Infant positive affect facilitates early expressive, but not receptive language

• This study comprehensively examines infant PA as it relates to language in early toddlerhood.
• Infant PA predicted early toddlerhood expressive, but not receptive, language.
• Activity Level, High Intensity Pleasure, and Approach predicted expressive language.
• Infant characteristics may differentially contribute to receptive and expressive language.
• Infant PA may support infants’ engagement with the environment, promoting expressive language.

Eighty-three mother–infant dyads participated in this study. Positive affect (PA) broadly, along with fine-grained aspects of PA, was measured at 10 months of age. Language was measured at 14 months. Infant PA predicted expressive, but not receptive, language. The implications of these findings are discussed.