Academic lexical coverage in TED talks and academic lectures

The coverage of academic lexis is compared in a TED talk corpus (2,483 talks, 5,068,781 words) and a corpus of Yale University lectures (708 lectures, 5,523,791 words). Academic lexis is defined by the Academic Word List (Coxhead, 2000), the Academic Vocabulary List (Gardner & Davies, 2014), and the Academic Spoken Word List (Dang et al., 2017). In all cases Mann–Whitney U tests found lectures had significantly higher coverage, with small effect sizes for lexis. This difference was smaller for academic tagged TED talks (n = 1379). When like-for-like disciplines were compared, lectures typically had greater coverage than their TED talk counterparts. An analysis of the cumulative coverage of types demonstrated a lower representation of the less frequent academic types in TED talks. A combined ratio and minimum frequency measure identified academic types which distinguish the genres. Pedagogical implications are discussed.