Agreement without understanding? The case of third person singular /s/

This study examined the comprehension of third person singular /s/ as a number agreement marker in children speaking Mainstream American English (MAE). Sixty-two MAE-speaking children aged 3-6 years were presented with a comprehension task where they had to focus on the verb as a clue to number agreement. Overall, results showed that only the 5- and 6-year olds were sensitive to third person singular /s/ as an index of subject number in comprehension, despite their earlier command in production. The implications for development of agreement are discussed.