Children’s acquisition of syntax from distributional cues to phrase structure

A signature of language is its phrase structure organization: words are grouped into phrases, which are the building blocks of sentences. How do children learn the groupings of words into phrases without consistent physical cues to phrase structure? One possible mechanism is statistical learning. Words (or word categories) occur in consistent sequences to form phrases (e.g. determiner + noun) with high transitional probabilities, while sequences of words that do not form phrases (e.g. auxiliary + noun) co-occur less consistently and have lower transitional probabilities. Adults can use this distributional information to learn phrase structure. However, the computational abilities required for this learning exceed what has previously been demonstrated for children. Here we asked whether children can do this learning. Children ages 5–10 listened to a miniature language containing distributional cues to phrase structure or to a control language lacking such cues. Children exposed to the phrase-structure language demonstrated robust learning of their language’s phrase and sentence structure. Children in the control condition did not acquire phrases and failed to learn their language’s sentence structure. The results demonstrate sophisticated computational abilities in young language learners and suggest that distributional learning is a powerful mechanism for children to acquire complex and abstract information about syntax.