The production of third-person /s/ on English verbs seems to be ahead of comprehension. Mainstream American English (MAE) is contrasted with African American English (AAE), in which /s/ is rarely supplied. Two studies explored what information children get solely from /s/ on the end of a verb. Sixty-five MAE- and 65 AAE-speaking four- to seven-year-olds participated in one of two experimental picture-choice comprehension studies. Neither group of four-year-olds could use the /s/ to determine if the event was generic rather than past tense on a verb (e.g. "cuts/cut"), or whether it was a verb or a noun compound as in "The penguin dresses"/"The penguin dress". MAE-speakers do not use the information in third-person /s/ alone until age five, and not reliably until age six years. In keeping with AAE production, AAE-speaking children do not use the information in /s/ at all in this age range.