Modification of teachers’ speech is the adjustment of the teacher’s speech in the classroom that can influence the opportunities, which learners have to participate in the instructional content, which includes linguistics areas such phonology, lexis, syntax, and discourse. The objective of this research was to describe the form of modifications in teachers’ speech used at 5th and 6th grade of English for young learners’ course at English Department of UMM which involved to the area of phonology, syntax, and discourse. Besides, it was also intended to know students’ responses toward modification on teachers’ speech at 5th and 6th grade of English for young learners’ course at English Department of UMM. This study employed a descriptive design. It is because the researcher described the modification of the teachers’ speech used at 5th and 6th grade of English for young learners’ course at English Department of UMM. The subjects were the eight semester students, who taught 5th and 6th grade of elementary students who joined on English for Young Learners course (EYL) at English Department of UMM. The research instrument was only observation. Based on the result of analysis of the data, it was found out that the EYL teachers of 5th and 6th grade at English Department of UMM adjusted/ modified their speech in the area of phonology. There were nine forms of speech modified by using length of pauses. The pauses used were about two seconds longer. They also adjusted/ modified their speech in the area of syntax. There were ten teachers’ speeches, which were modified in the form of shorter sentences. They downward the sentence from its normal form, two until five shorter. Finally, they modified their discourse. There were seven forms of self-repetition. The teachers repeated for two until four times as much during classroom interaction. Moreover, the students’ responses toward teachers’ speech modification were also found to be various; there were choral, initiated, silent responses, and other behavioral responses. There were five forms of students’ choral response, nine forms of students’ initiated response, two forms of students’ silent response and ten forms of students’ response in another behavior found out from this study.