It is often said that words have power. Language is integral to our survival as a social species but is more than just a tool for communication. Language is also a window into our inner lives, motivations, and social relationships, and can be used to achieve social goals. One way we can use language to achieve our goals is to strategically adjust the way that we communicate: We can adjust aspects of our communication (such as accents, tone, pitch, sentence construction, down to use of individual words) to be similar to our communication partners (known as convergence). In doing so, we can strategically enhance feelings of liking and rapport. In contrast, by adjusting communication to be dissimilar to our communication partners (known as divergence), we can demonstrate differences and increase social distance. In this talk I discuss a line of research which explores how changes in a particular aspect of language, our non-conscious use of function words, can be used to identify whether someone is leading a conversation, following, or attempting to manipulate their conversational partner. I show that individuals who adjust their function word use to be similar to that of their conversational partner are often in a lower position of power and change their function word use to engender liking for their own personal gain. Such ‘power moves’ in language use are associated with manipulative personality traits, akin to those known as the Dark Triad of personality. These findings generalized across posts in an online community forum, face to face interactions, and computer mediated interactions. I discuss the theoretical and forensic implications of this work for identifying types of individuals simply by their use of words.