Interactive discourse structuring is used to guide listeners through on-going speech and has been shown to have a positive effect on lecture comprehension, particularly in L2 settings. As mobility increases in the academic world, there are more opportunities for lecture events characterized not only by linguistic/cultural diversity, but also by unfamiliarity between lecturers and audiences. In these situations, interactive discourse structuring may have an especially important role. This study compares interactive discourse structuring used by guest lecturers (both L1 and L2) versus L1 classroom lecturers. Using corpus methodology, interactive discourse structuring was found to be most frequent among L2 guest lecturers, least frequent among L1 guest lecturers, with L1 classroom lecturers falling in the middle. The results suggest that linguistic/cultural diversity has more influence on discourse structuring than participant unfamiliarity. In addition, the analysis revealed other trends, particularly the very wide range of vocabulary used in discourse structuring expressions by all speakers. The findings can be implemented towards developing more authentic academic listening materials, as well as guidelines for both native and non-native guest lecturers who interact with international audiences. (Contains 2 tables.)