The present thesis is comprised of two corpus-based studies. The first study examined (1) the vocabulary demands of spoken academic English and (2) the coverage of Coxhead's (2000) AWL in Academic speech. Transcripts of 62 lectures and 7 seminars form the MICASE corpus were collected and analyzed. The findings suggested that coupled with proper nouns and marginal words, knowledge of the most frequent 3,000 or 7,000 word families is needed to reach 95.55% and 98.03% coverage respectively of the combined lectures and seminars corpus. The second study compared the lexical coverage of Garnier and Schmitt's (2015) phrasal verb list (PHaVE) and the most frequent 150 AWL lemmatized verbs in academic speech. The analysis was carried out on a 2,431,351 running-word corpus created from the BASE and the MICASE corpora. The finding indicated that the PHaVE List accounted for slightly higher coverage figures than the AWL in the study corpus.