Researchers suggest that children don't necessarily pick up new words just by overhearing a conversation, but build their vocabulary from direct conversations.
A study including 30 two-year-olds and their families found that overheard speech didn't compute. What did stick, were the chats that the toddlers had directly with adults. It wasn't enough for them to just listen to someone else's conversation, they had to take part.
Having direct back-and-forth conversations helped to build these kids' vocabularies.
