Children As Young As 19 Months Understand Different Dialects

In this experiment, 15- and 19-month-old American toddlers looked at a colored checkerboard on a monitor in order to hear sets of familiar words or unfamiliar words. They completed two tests, one with their own American dialect, and the other with a Jamaican English dialect.

The results, described in Psychological Science, a journal of the Association for Psychological Science, suggest that phonological constancy is already evident by 19 months of age, but is not yet present at 15 months. Both ages listened longer to familiar words than to unfamiliar words in the American dialect, indicating they recognize and prefer words they know. But the 15-month-olds failed to show this preference for the Jamaican dialect, suggesting poor recognition of Jamaican-accented words. However, the 19-month-olds showed the same familiar-word preference in the Jamaican accent as in the American accent, indicating cross-dialect phonological constancy for words.

The authors conclude that phonological constancy, along with the complementary ability to differentiate words from similar-sounding words or nonwords (known as phonological distinctiveness), "together serve as a solid foundation on which children rapidly build a vocabulary, and later extrapolate from spoken language to the world of reading."