1. A computer-implemented method comprising: obtaining a set of language indicators that comprises an indication of a language used by a second user that is socially connected to a first user, each language indicator related to a language potentially preferred by the first user; by a processor, applying a set of rules to the language indicators to obtain a set of preferred languages for the first user, the set of preferred languages being ordered according to a determined likelihood that each language is the first user's primary preferred language; and localizing a first application based upon the highest-order preferred language.