The Role of Siblings on Infant Language Exposure in Daylong Audio Recordings

The language children hear every day is important for language learning. Different sets of speakers may lead to different kinds of speech: Speech directed at a child or speech directed to another adult or a sibling. We aimed to quantify how the presence of a sibling, specifically, affects dynamics of speech in a home. Using day long audio recordings from homes in the United States, we measured the amount of target child-directed and overheard speech in the home of infants in families with and without older siblings. Infants with an older sibling experienced significantly more overheard speech and significantly less speech directed to them, than infants without an older sibling. However, families with and without older siblings did not differ in the total amount of child-directed input, directed to either sibling. These findings suggest a more complicated relationship between overheard speech and language learning.