Although sociologists have a long history of making claims about people’s internal conversations, these claims are based on little or no evidence. We present results from the first sociological analysis of a large number of self-reported internal conversations, focusing on two interconnected properties of internal conversations: their uses and what internalized others appear and speak in them. We developed taxonomies for categorizing internal conversations based on these properties. The majority of internal conversations in our collection were used to prepare for action, such as with rehearsals, self-direction, and to-do lists. Internalized others appeared in over two-thirds of internal conversations but spoke in fewer than a fifth of them. Internalized others were most likely to speak in rehearsals and other internal interactions, which involve mentally running through an interaction with one or more other people.