The research is aimed at (1) identifying the the languages used by teachers inEnglish classroom; (2) finding out the Discourse Markers (DMs) used by teachers inEnglish classroom; and (3) finding out the functions of DMs used by teachers inEnglish classroom.This research uses qualitative case study method. The research was carried outin April to June 2014 in SMA Negeri 3 Surakarta which is located at Jln. LaksamanaSukardi R.E.Martadinata 143 Surakarta for the regular program and at Jln. Prof.W.Z.Yohanes Surakarta for the acceleration program. The sources of the data wereevents, informants, and documents. The data were collected through observation,interviews, and document analysis. The teaching and learning process were recordedand transcribed. The data were analyzed using interactive model of qualitative dataanalysis technique, which includes data reduction, data display, and drawingconclusion/ verification.Based on the observation, interviews, and document analysis, it can beconcluded that: (1) both teachers use more than one languages of instruction inEnglish classroom. T1 uses 75% of English, 20% of Indonesian, and 5% of Javanesein her talk. T2 exhibits a balanced use of English and Indonesian in Englishclassrooms with the proportion of 50% - 50%. (2) the DMs used by the teachers inthe classrooms cover DMs in English such as okay, so, filler er and em, well, now,and, but, because, and then, next, if, by the way, and I mean, DMs in Indonesian suchas oke, jadi, nah, bentar bentar, and tapi and DM in Javanese i.e. sik sik. Thefindings suggest that the use of English DMs outnumbers Indonesian and JavaneseDMs with DM okay, so, and then, and er are the most preferable DMs both teachersuse in the teacher talk due to the high multi-functionality in academic discourse (3)The research findings suggest that the textual functions served by the DMs used bythe teachers in the classroom discourse are as follows: (a) to mark the opening of thediscourse, including claiming the students’ attention (okay, so, oke); (b) to signaltopic switch, including the boundaries of classroom procedures (okay, oke, well, bythe way, now, nah); (c) to mark the closing of the discourse (okay); (d) to keep thespeaking turn (er, em, bentar-bentar, sik-sik); (e) to relinquish the speaking turn(okay, so); (f) to indicate result or conclusion (so, jadi, nah); (g) to signal contrastiverelation (but, tapi); (h) to mark sequential relations (next, and then); (i) to signal thecontinuation &addition (and); (j) to indicate repairs of the speech (I mean); (k) toshow condition relation (if); (l) to show causal relation (because).The fact that the use of DMs is viewed beneficial to the organization of thediscourse implies that there should be an increased awareness on the use of DMs inteacher talk for it can help teachers to better-achieve the instructional objectivesthough the teacher talk. Teacher education, therefore, should facilitate uptake ofDMs as a significant linguistic feature.Keywords: Discourse Markers, teacher talk, classroom interaction