Distinguishing One’s Own Voice from Those of Others: A Function for Private Speech?

The aim of the study reported here was to test a new hypothesis about the function of private speech, namely that children’s private speech in social contexts presents them with an opportunity to distinguish their own voices from those of others. Data on the social and private speech of 22 five-year-olds were collected during single hour-long group play sessions. In a later session, children heard extracts from an audio recording of an earlier group discussion, and were asked to state which of each pair of extracts contained their own speech. It was found that children’s performance on this speech recognition task was positively correlated with both proportional and frequency measures of private speech. There was no relationship between the speech recognition measure and frequencies of social speech or overall verbosity; and performance on a test of children’s ability to recognise their own speech in isolation was no better than chance. We suggest that these findings are consistent with private speech having a specific function in the development of an understanding of oneself as a speaking agent among other such speakers.