Maturity of teachers verbal style derives from two aspects; One is the potential factor (the internal nature),the other is its manifestation (external).

The style of a teachers language should have its own unique aesthetic character.

Education for all-round development makes a new requirement for teachers language.

The teachers language is a kind of professional language.

In the framework of metafunction of functional grammar,this paper is to analyze and discuss the functions of teacher talk in terms of its cognitive function,appraisive function and interactive function in teacher-student interaction in a foreign language teaching class.

Following the social constructivist theory of learning, this present study primarily examines the effects of teacher talk on children’s learning in preschool English-medium activities.

Based on the speech act theory, the teacher talk in foreign language classrooms of China University of Geosciences (Beijing) is observed and analysed.

This paper, by comparing three types of language teachers , intends to point out that a language teacher should not only have a knowledge of his teach ing subject matter, or his skilful use of teaching methods but also his developi ng capacity to generate a psychological climate conducive to high quality learni ng.

Knowing these features of interlanguage should be very helpful for the making of grammatical syllabus,improving the efficiency of language teaching and language teachers teachin g,etc.

However, the related research on language teachers in secondary schools is relatively poor.