We report the results of a 2-year longitudinal comparison of grade 3 and grade 4 English-as-a-second-language learners in an experimental, comprehension-based program and those in a regular (i.e., more typical) language learning program. The goal was to examine the extent to which sustained, long-term comprehension practice in both listening and reading--in the virtual absence of any speaking--can help develop learners' second language (L2) pronunciation. We analyzed learners' sentences from an elicited imitation task using several accuracy and fluency measures as well as listener ratings of accentedness, comprehensibility, and fluency. We found no differences between the two programs at the end of year 1. However, at the end of year 2, there were some differences--namely, in the listener ratings of fluency and comprehensibility--that favored learners in the regular program. These findings highlight the beneficial effects of comprehension practice for the development of L2 pronunciation but also point to some potential limits of this practice.