Agustinus Semiun Pengarang Soleman Dapa Taka Pengarang Hilda Nalley Pengarang

ABSTRACT The present paper presents why the use of English by EFL teachers is important and strongly required with a specific reference to language learning, language teaching, and classroom interaction theories. The writer (as a tutor) made use the observation data on micro-teaching practice sessions done by PLPG teachers as well as data of former article by the writer in a number of journals. This article claims that the use of English by the teachers impacts, on the successful process of acquisition or learning on the part of the students and the successful teaching on the part of the teachers. In short, the theories discussed in this- article highlight the importance of the use of English by the teachers to provide exposure for the students' comprehensible input, while classroom interaction theory highlight the importance of the use of English of the teachers to motivate the students to get involved in classroom interaction to develop students' interlanguage. Key words: Importance, Use of English, teaching and learning theories