Discourse markers can have various functions depending on the context in which they are used. Taking this into consideration, in this corpus-based research, we analyzed and unveiled quantitatively and qualitatively the functions of four discourse markers in academic spoken English. To this purpose, four discourse markers, i.e., "I mean," "I think," "you see," and "you know," were selected for the study. The British Academic Spoken English (BASE) corpus was used as the data gathering source. To detect the discourse markers, concordance lines of the corpus were carefully read and analyzed. The quantitative analysis demonstrated that from among the four discourse markers, "you know" and "you see" were the most and the least frequent ones in the corpus, respectively. In line with the quantitative analysis, the qualitative analysis of the concordance lines demonstrated that there were various functions with regard to each of the four discourse markers. The findings of this study can have implications in fields such as corpus-based studies, genre analysis, and contrastive linguistics.