Statistical analyses of task-based lexicons found in the classroom speech of native and non-native English language instructors

摘要

公立高校1学年の同一クラスにおいて英語の授業をビデオ撮影し（1回45分、6ケ月、合計49回）、母語教員（ET）3名、非母語教員（JT）1名、教科書準拠録音（CD）の映像・音声・書き起こし文字列からなるコーパスを作成した。語彙の種類や頻度、発話あたり単語数、n-gramなどを分析したところ、ET・JT・CDの発話の違いはそれぞれの役割の違いを反映していること、自然発話に見られる言いよどみなどの現象はET・JTの発話に固有であること、発話あたり単語数の多い文章はCDに多く見られること、ET・JTの言語能力は同等であるらしいこと、などがわかった。ETとJTが役割を交替・分掌・共有しつつ互いの語彙特性を学び合えば、教員が使用する英語が増加すると思われる。%We compared language-class English spoken by three English teachers (ET), a Japanese teacher (JT), and a CD produced by the publisher of the textbook used in class (CD). A high school English language class was videotaped and transcribed for one semester (49 class periods of 45 minutes each). Word frequencies, n-grams, and utterance lengths show that (a) ETs focus on oral interaction, particularly on open-ended questions that intend to elicit longer spoken responses from students, (b) the JT directs classroom behavior, defines lexical items, explains syntax, and asks short questions, and (c) the CD presents longer, well-formed utterances with characteristics of read speech. Our findings suggest that (a) ETs might become aware of students' intent and language limitations, (b) JTs might engage in dialog with their students, and (c) ETs and JTs currently provide the sole source of disfluencies such as filled pauses, false starts, and repairs.