Vocabulary suitability of science TED talks for English for science teaching and learning

With a view to advancing their students' listening comprehension and vocabulary, English for Science teachers are frequently in search of new and interesting audio and video materials. TED Talks on science topics are a good option for this purpose. But just how suitable, vocabulary-wise, are they for English for Science learners? This study explores the lexical profile of TED Talks on science and compares it against non-science TED Talks and science academic lectures. We use a 5-million-word TED Talk corpus, with a 1.3-million-word science subsection. Of the two categories of TED Talks, it is the science ones that are lexically more similar to science academic lectures. Science TED Talks also feature significantly more technical vocabulary than non-science TED Talks. Reasonable listening comprehension is achieved at 4,000 words for science TED Talks, while ideal comprehension is achieved at 8,000 words for both categories. These results recommend science TED Talks for English for Science listening.