Proceedings of the Annual Meeting of the Cognitive Science Society

For the claim that child-directed speech (CDS) aids language development to be generalisable, superior learning from CDS compared to adult-directed speech (ADS) must be demonstrated across multiple input domains and learning outcomes. To determine availability of relevant evidence we performed a study space analysis of the research literature on CDS: 942 peer-reviewed studies were coded with respect to CDS features, learning outcomes and whether they included a comparison between CDS and ADS. The results showed that only 290 (16.2%) studies compared outcomes between CDS and ADS, almost half of which focussed on the ability to discriminate between the two registers. Only 20 studies showed learning benefits from CDS for some morphosyntactic and lexico-semantic features and none for pragmatic and extra-linguistic features. Thus, CDS-ADS comparison studies are very unevenly distributed across input features and outcome measures. Until these research gaps are filled claims that CDS facilitates language development should be moderated.