One of the advantages of having students work in pairs on language-related tasks is that teachers and researchers can listen to what the students say as they carry out their assigned tasks. What they say offers insights into the students' beliefs about the target language they are learning and using, and reflects the cognitive processes they use to produce an utterance. In this paper, we analyze dialogues between pairs of eighth grade French immersion students about avoir besoin de. Our analysis provides insights that allow teachers to help students more accurately encode the meaning they wish to express. Teachers and researchers are also given an insider's view of how learners make use of what they already know to support their learning of an additional language.