Even at the tender age of 19 months, children can understand different dialects of a language. Researchers term this skill 'phonological constancy'.
Everyday, we come across different accents. Even when a speaker of another English dialect pronounces words differently than we do, we are typically able to recognize their words.
Now, psychologist Catherine Best from MARCS Laboratories, University of Western Sydney, along with colleagues from Haskins Laboratories and Wesleyan University, has shed light on the early development of this cross-dialect skill.
In the study, 15- and 19-month-old American toddlers looked at a coloured 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 suggested 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.
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 researchers said that phonological constancy, along with the complementary ability to differentiate words from similar-sounding words or non-words, "together serve as a solid foundation on which children rapidly build a vocabulary, and later extrapolate from spoken language to the world of reading."
The study has been described in Psychological Science, a journal of the Association for Psychological Science.