The linguistic sciences will always be behind the teacher. They have a direct
influence on his approach to language teaching. Every teacher has an approach
(conscious or unconscious) to language teaching. The task of language teaching
prompts the teacher almost invariably to think about the nature of language; for
example, his theory of language will determine whether he presents the language
analytically or non-analytically to the learners. The rationale for his decision will
imply a view of the nature of language or a theory of language. His method •
such as a decision about drill work - will likewise be based on a view of second
language acquisition. A theory of second language teaching is therefore an
important aspect of teaching and learning. It is generally agreed that what
happens in the classroom will actually determine the success of the teaching; the
major determinant of what happens is the second language acquisition theory.