Emoji can modify a textual utterance, constitute a stand-alone speech act, or virtually perform an action. These three broad types of pragmatic function are usually treated separately in the literature when they are treated at all. We classify these functions in a systematic, unified manner by drawing on the classic speech act notion of illocutionarity. We present a conceptually motivated typology that accounts for the three basic types of emoji function, as well as most pragmatic functions reported in previous emoji research, illustrating it with data from American and Chinese social media. The scheme can serve as a practical heuristic to guide empirical research on emoji use and a theoretical anchor for pragmatic studies of other graphicon types.