This qualitative and quantitative study applies conversation analytic methodology to the examination of mutual intelligibility, and then quantifies the segmental repairs and segmental adjustments that were required to maintain intelligibility in English as a Lingua Franca interactions among students at a Japanese university. In the qualitative portion, sequential analysis was used to ascertain the segmental repairs that were utilized to maintain mutual intelligibility and to identify the pronunciations that interactants oriented to as unintelligible and intelligible, which can then be compared to determine the segmental adjustments that changed an unintelligible pronunciation into an intelligible one. In the quantitative portion, the segmental repairs and the segmental adjustments were quantified in order to assess which kinds of segmental repairs and segmental adjustments are most frequent. This study concludes that reactive repair is the most frequent segmental repair, and modification is the most frequent segmental adjustment.