Sequence structure in children’s speech reveals non-linear development of relations between word categories

Why do children learn some words earlier than others? Can children's speech patterns reveal how their evolving models of language determine what they learn? This study presents a systemic analysis of children's speech, using low-dimensional embeddings to examine how the contextual knowledge reflected in their utterances reorganizes as linguistic experience increases. Our results suggest that the order and position of words in sequences produced by children from different age groups reflect changes in the way they represent categories of words. Rather than being ungrammatical, children's utterances appear to be structured by temporary grammars, which optimize the distribution of information in sequences. We show how semantic networks reorganize to support learning and suggest that English provides functionally ambiguous (multipurpose) categories to aid the reorganization of semantic spaces. These findings are somewhat counterintuitive, as they suggest that not knowing the exact meaning of words can facilitate both learning and communication.