  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 these adult inferences as listeners
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 modeling 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.
