Teacher talk is the major even the only source of language input for many foreign language learners in China. Therefore, the quality of teacher talk plays a crucial role in learners'language learning. Research on teacher talk can be roughly divided into two main dimensions, i.e. linguistic features and interactional features.The present study which is more related with the linguistic features of teacher talk aims to analyze teacher talk varies when addressing students in English classroom at different grades. The study exams three main aspects, namely, ratio of Chinese and English use, lexical complexity (type-token ratio, rank of words, mean length of word and amount of long words) and syntactic complexity (mean length of utterance, frequency of subordinate clauses and frequency of passive constructions). With classroom observation and transcription, some major findings are summarized as below.The study yields the following findings:1) in the aspect of ratio of English and Chinese use, there is increased English use and reduced Chinese use with the ascending of grades, though the difference is not statistically significant; 2) in the aspect of lexical complexity, the type-token ratio of all the teachers are low; the mean length of word is short; teachers tend to use basic vocabulary; there is significant variance in the amount of long word use between the teachers in higher grades and those in lower grades; 3) in the aspect of syntactic complexity, the mean length of the teachers'utterance decreases firstly and then gradually increases with the ascending of grades, and significant difference is found between two grades. There is gap but no variance in both the frequency of subordinate clauses and the passive constructions between the teachers in higher grades and those in lower grades.The findings above give insights into language teaching and learning, that is teachers should raise the awareness of adjusting their classroom language with the development of learners'language proficiency. Meanwhile, the present study also provides reference for the related future research. |