This research study investigated how the teachers and students at a Persian heritage language class acknowledged and modified their affective behavior based on the affective feedback they received from one another. The notion that interactants can modify their affective output in such fashion is referred in the literature as affective alignment (Ochs, 1988). By using linguistic anthropological methods, audio and video recordings of naturally occurring conversation involving 17 students and two teachers were analyzed for the use of verbal and non-verbal affective behavior. The analysis showed that students actively participated in an on-going negotiation of affective practices with their teachers. Moreover, learning the heritage language was related to and dependent upon other affective factors beyond students' immediate educational and instructional need. These findings provide us with a better understanding of the influence of the teachers' and students' affective behavior on one another, and on students' acquisition of their heritage language.