Although there seems to be no doubt that English as a lingua franca paradigm has affected the focus of English language teaching toward the issue of mutual intelligibility, studies involving only non-native English speakers (NNS-NNS interaction) are still in their infancy. Using a sequential analysis, this study examines how Japanese learners of English communicate with non-native English interlocutors who do not share their L1 background, and analyzes how they overcome non-understanding when a breakdown in communication occurs from the perspective of English as a lingua franca. Data from video-recording and interviews were collected and the interactions in the three groups, including L1 speakers of Japanese, Malay and Chinese, were analyzed. The analysis reveals that ELF users' interactional modifications probably vary depending on the interlocutors and the given context, and also that non-understanding might not be overcome only through a particular modification pattern, but that a few different types of modifications and negotiation of meaning may be needed for a successful communication among the interlocutors. These observations suggest that English as a lingua franca interaction is cooperative and mutually supportive. Based on these findings, raising teachers' awareness of the lingua franca role of English and the need for implementing the training of negotiation skills for a successful communication are also discussed.