Inner speech is (roughly) the phenomenon of silently speaking to oneself. Although it is highly salient in most people’s inner experience, it has received very little attention from philosophers of mind. This paper takes up the following question: what exactly does inner speech consist in? It reviews the suggestion of the great psychologist, Lev Vygotsky, that inner speech is essentially a way of thinking in meanings; it seeks to supplement this account by supporting the claim (recently endorsed by a handful of philosophers) that inner speech involves auditory imagery; and it argues that the sense of agency which derives from producing the auditory imagery in any given inner speech utterance also influences the meaning of that utterance.