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How adults understand what young children say


Children’s early speech often bears little resemblance to that of adults, and yet parents and other caregivers are able to interpret that speech and react accordingly. Here we investigate how adult listeners’ inferences reflect sophisticated beliefs about what children are trying to communicate, as well as how children are likely to pronounce words. Using a Bayesian framework for modelling spoken word recognition, we find that computational models can replicate adult interpretations of children’s speech only when they include strong, context-specific prior expectations about the messages that children will want to communicate. This points to a critical role of adult cognitive processes in supporting early communication and reveals how children can actively prompt adults to take actions on their behalf even when they have only a nascent understanding of the adult language. We discuss the wide-ranging implications of the powerful listening capabilities of adults for theories of first language acquisition.

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Fig. 1: Schematic overview of the Bayesian spoken word recognition models and experiments.
Fig. 2: Performance identifying intelligible/unintelligible vocalizations by model.
Fig. 3: Average posterior surprisal of the transcribers’ recovered word interpretation under each model with the phoneme-based likelihood.
Fig. 4: Properties and performance of the phoneme-specific likelihood.
Fig. 5: Child-specific model performance.

Data availability

All data used to train language models come from public child language transcripts retrieved through the Child Language Data Exchange System (CHILDES50) using childes-db74. Test datasets come from the Providence corpus27, which have been made publicly available through the PhonBank75 project ( For this project data were obtained through childes-db74 (

Code availability

All model training and analysis code is available through our GitHub repository at Fine-tuned models and pre-processed child transcripts can be accessed through our Open Science Foundation repository at


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We thank J. Mankewitz, S. Nair and R. Jansen for providing feedback on early drafts as well as members of the Computational Psycholinguistics Lab at MIT and the Bergelson Lab at Duke for valuable discussion. We thank K. Gorman, T. Eisape and P. Qian for several helpful technical consultations. S. Zhi contributed to the implementation of the pronunciation module. This work was supported by NSF grants BCS-1551866 (R.P.L.), BCS-1844710 (R.P.L.) and BCS-2121074 (R.P.L.); NIH grant 1F32HD097982 (S.C.M.) and DP5 OD019812-01 (E.B.); and the CONVO grant to MIT Brain and Cognitive Sciences from the Simons Center for the Social Brain (R.P.L., S.C.M. and N.H.W.). R.F. received no specific funding for this work. The funders above had no role in study design, data collection and analysis, or the decision to publish or preparation of the manuscript.

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S.C.M. and R.F. conceived the project and designed the analyses. S.C.M. and N.H.W. developed the models and conducted the analyses E.B. and R.P.L. supervised the project. All authors wrote the manuscript and provided critical feedback.

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Correspondence to Stephan C. Meylan.

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Meylan, S.C., Foushee, R., Wong, N.H. et al. How adults understand what young children say. Nat Hum Behav (2023).

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