In psycholinguistic experiments on language processing, researchers have traditionally focused on either comprehension or production. However, real-life, communicative language use happens most often in an interactive setting, involving rapid turn-taking between interlocutors. In such a setting, listening to a turn probably overlaps with preparing an answer to this turn. In the current EEG experiment, participants answered quiz questions, asked by the experimenter. Unknowingly to participants, these questions were pre-recorded, while the experimenter gave live feedback on participants’ answers. Questions appeared in two different conditions. Participants could confidently guess the answer to the question either halfway through the question (e.g., "Which character, also known as James Bond, appears in the famous movies?"), or only when they heard the last word(s) (e.g., "Which character, who appears in the famous movies, is also known as James Bond?"). ERP results showed a small N400 effect, followed by a large positivity at the moment within the question that the answer started to become apparent (the critical point). In the frequency domain, an alpha/mu desynchronization effect was found, starting within 500 milliseconds after the critical point. A follow-up control-experiment in which participants only listened to the questions and tried to remember them, showed a qualitatively similar pattern in the ERPs, but with a larger N400 and a smaller positivity. The alpha/mu desynchronization effect was absent or at least very much redu ced. We tentatively interpret the alpha/mu desynchronization from the main experiment as a signal of response preparation, starting quickly after an appropriate response can be retrieved