Vocabulary profile, lexical density and speech rate of science podcasts: How adequate are they for EAP and ESP listening?

Abstract

One potential source of authentic input for English for Academic Purposes (EAP) and English for Science and Technology (EST) listening could be science podcasts. In this study, we examine the vocabulary level of this genre, as well as the amount of the common specialized, i.e. academic and scientific vocabulary it contains. Additionally, we study its lexical density and speech rate. These properties are examined on a corpus of 126 science podcasts produced by the journal Nature, the American Association for the Advancement of Science (AAAS) and the magazine Scientific American. These are compared against those determined for a corpus of lectures in general (the MICASE lectures) and a corpus of science lectures in particular (the MICASE’s science-lecture subsection). On the one hand, science podcasts were found to contain a good amount of both academic and scientific vocabulary, as well as to have a very similar lexical density to that of lectures. On the other hand, their vocabulary level and speech rate were somewhat higher than those of lectures. Based on the analysis, we recommend the use of science podcasts for both EAP and EST listening for advanced learners. For learners with lower proficiencies, vocabulary support and/or adjusting the speed of the science podcasts is advised.