This paper aims to identify and define the different linguistic functions that emoji can carry in French and English computer-mediated discourse (CMD). Emoji are graphical icons, representing attitudes or concepts, that can be used on any smartphone or computer with a variety of communicative roles inside a conversation. Using a multimodal corpus containing 1200 emoji and the messages in which they were used, we tested an initial typology of emoji functions inspired by previous frameworks. The quantitative analysis of the data, along with the detailed examination of specific examples, led to the construction of a new, more refined typology consisting of three primary functions (expressive, interpretative and referential) and five secondary functions (relational, politeness, emphatic, structural and aesthetic).