This study investigates the effects of different voice-chat conditions on Korean EFL learners’ topic negotiation according to proficiency levels. Participants consisted of 123 EFL learners who enrolled in Speaking English I at a Korean university. They were divided into three proficiency levels: beginning, intermediate, and advanced. Then, they were further classified into two experimental groups: human-to-human voice-chat and human-to-robot voice-chat. During the experiment, participants practiced speaking with two different voice-chat conditions. Chat scripts were chosen at random and analyzed by counting the number of topic negotiation moves. With the descriptive statistics, paired samples t-tests and independent t-tests were administered. Major findings are as follows: Beginning learners in human-to-robot voice-chat initiated more topics, and avoided the topics less often, as time went by. Intermediate and advanced learners in both voice-chat conditions stayed on the topic more often, over time. Intermediate learners became less likely to avoid the topic in human-to-robot voicechat, while advanced learners did in human-to-human voice-chat. In an interview, participants in both experimental groups revealed positive reactions to voice-chat experience. Based on these findings, pedagogical suggestions are provided for the effective implementation of voice-chat in EFL contexts.