In foreign language education today, the use of the first language (L1) in the second language (L2) classroom is a highly debated topic. Entire pedagogies are designed to limit the amount of the L1 in the L2 classroom towards a goal of total immersion. Contrastively, I argue that the question of "how much" is leading us in the wrong direction. The question about the L1 in the L2 classroom needs to be a more critical one of "what" should be promoted and "why." It is important to gain insight into how students are using their L1 in the language classroom because the L1 is an important psychological tool for learners to mediate their experiences (Dailey-O'Cain & Liebscher, 2015; Swain & Lapkin, 1998; 2000). This paper aims to contribute to the field's understanding of students' functional uses of the L1 in the L2 classroom. Through an analysis of learner-learner interactions, there are clear differences in the functions being served by the L1. The discussion of the data includes: which communicative functions might still be appropriate in the L1, which we should hope to transfer, and how these affect language learning guidelines.