Lexical types and tokens found in the classroom speech of native and non-native English language instructors in a Japanese high school

抄録

Within the context of English language taught solely using English language at Japan's secondary schools, no research quantifies the differences between native instructors (first language English, may or may not speak Japanese) and non-native instructors (first language Japanese; second language English). We developed a video corpus of an English language classroom, and examined the speech of 3 native and 1 non-native instructors. The corpus contains 49 English lessons of 45 minutes each in a Japanese public high school with monolingual learners of English as a foreign language. The native and non-native instructors occasionally taught together. Almost all speech in the lessons was in English. We compared lexical tokens and types found in our transcriptions with a collection of typical classroom English dialogues, and a wordlist created from large bodies of written and spoken English. We obtained the distributions of words, and words preferred by either native or non-native instructors. Results suggest that (a) native and non-native instructors share a core vocabulary of classroom English, (b) native instructors teach vocabulary depth via open-ended conversations, (c) non-native instructors teach vocabulary breadth via textbook explanations, and (d) native and non-native instructors differ in teaching roles but not in language ability.