During spoken interaction with peers, ESL or ELF learners use peer feedback to negotiate and converge on mutually intelligible pronunciation. In contrast, for EFL learners who interact mainly with same-L1 peers, it is not clear whether the giving and receiving of peer feedback on intelligibility can facilitate uptake leading to improved pronunciation. However, it has been suggested that same-L1 learner pronunciation feedback requires ample time and a narrow focus, conditions that could be realized in a CMC environment. This study investigates the effect of modality--face-to-face (FtoF) or computer-mediated (CMC)--of peer feedback on the intelligibility of 83 Japanese university students' /l/ and /r/ in four target words. After discrimination and pronunciation training, treatment consisted of participants making peer intelligibility judgments in two modalities. The FtoF group pronounced and provided immediate feedback in pairs, while the CMC group recorded utterances that were randomly delivered to peers for asynchronous intelligibility judgements. The participants' pre-, post-, and delayed posttest recordings (956 utterances) were rated for intelligibility. For each target word, Generalized Estimating Equations examined the effect of group, initial discrimination ability, change in listening discrimination ability, and initial pronunciation confidence. The CMC group was significantly more likely to be intelligible for post-treatment singleton-/r/ and delayed posttreatment /l/-clusters. The results suggest that, depending on the intended target, intelligibility feedback from same-L1 peers in a CMC environment does not hinder and may promote pronunciation development.