Yum, Hea-Young(1955). The "Input Hypothesis" and the Second Language Teacher. Linguistics vol. 3. Although there are many other factors which affect the language learner`s proficiency such as personality, age and first language, the learner`s input has been emphasized by many researchers (Krashen 1976, 1977; Dulay et al 1981). Especially, Krashen`s "input hypothesis" emphasizes the comprehensible input to language learners. His thesis is that language learners must give an i+1 level of teaching to language learners. Thus, the second language teacher should know the current level of proficiency and develop an one-level higher teaching program. In my paper, I will consider some factors which need to be considered to make a comprehensible input for language learners. Particularly, I will consider linguistic input for language learners. Phonological, Morphological, syntactic, Semantic, and Pragmatic considerations to make a good teaching plan will be discussed in this paper. As a conclusion, I will argue that the second language teacher needs to have Contrastive Analysis for inter-language influence, and Error Analysis for intra-linguistic influence to the students.