This study investigates how children aged 4 to 12 years participate in /u/-fronting, a phonetically conditioned change in Ontario English in which the high back vowel /u/ is initially more fronted after coronal consonants than in other contexts. A picture naming task was used to elicit vowel tokens from children and their parents, and F1 and F2 measurements were extracted using FAVE. Children in all three age groups (4-6, 7-9, 10-12 years) were found to have significantly higher F2 values for /u/ (indicating more fronting) than adults in the non-coronal environment. This pattern does not appear to follow the predicted pattern of incrementation of sound change by older children. Instead, the findings may reflect overgeneralization of /u/-fronting, with young children extending the change to a new phonetic context during acquisition, or an earlier start to the incrementation of this variable in this population.