Generally, people use a language or a specific language form (i.e. linguistic variety) to communicate with each other or to hide their speech from outsiders. In Ethiopian geopolitics, furthermore, the criteria of a “common language” became the decisive factor for people to “count” as a distinct social – i.e. ethnolinguistic – group. Accordingly, the government of current Ethiopia re-divided the country into administrative units – Woreda (smaller district), Zone (larger region), and confederative regional states – along ethnolinguistic lines, based on the assumption that a “common language” also implies that its speakers have a common home area, follow common cultural practices, believe in a shared history, etc. Thus, the knowledge of a specific language became an important economic and sociopolitical resource in Ethiopia. Despite its important role in Ethiopian politics, language is a rather vague category. As ethnic identities are social constructs, the composition of ethnolinguistic groups and consequently their languages is subject to change. Moreover, a language consists of various regional and social sub-varieties and registers whose co-existence hinders a consistent method to decide whether they should represent different languages, or dialects of the same language. This paper will give a general overview about Ethiopian languages. After a brief discussion of the main defining criteria of a language, it will elaborate on regional and social variation in Ethiopian languages, with a bias on Ethiosemitic, the language family I know best. Finally, I will make some remarks on multilingualism, language shift and ethnic identity.