Previous research on foreign language classroom participation has shown that oral production has a privileged status compared to less salient forms of participation, such as mental involvement and engagement in class activities. This mixed-methods study presents an alternative look at classroom participation by investigating the relationship between second language (L2) thoughts and L2 speech in German as a foreign language learners in a language program in the United States. At four points during an academic semester, 16 students answered an in-class survey that aimed at recording students' estimations of how much of their thoughts had been formulated in the L2 and how much of their speech had been articulated in the L2. A small subset of these students participated in individual stimulated recall interviews to gather their own reflections on their thought processes and L2 speech production. Results show that students' L2 speech production is conditioned by a complex interplay of variables, which results in a mismatch between self-reported L2 thoughts and L2 speech. Several explanations derived from interview data are offered to account for this divergence, such as motivational tendencies, misperceptions of L2 use, the production of rehearsed speech, metalinguistic thoughts in the first language, and conceptions of silence as a valid form of participation. Pedagogical implications are discussed.