Multilingualism is the global norm, but the implications of this for cooperation and public goods provision are seldom studied. We test experimentally whether
the language in which a public goods game is played affects subjects' contributions amongst a bilingual population, in Eastern Uganda. We find that subjects on
average contribute a quarter less in the more local language. This treatment effect is solely driven by those most associated with the local identity, which is known
to value autonomy as an ideal. The language used to conduct the game makes one of two identities salient but both are shared by all subjects. However, the
heterogeneous effects imply identities have different weights or interpretations for diferent subjects. This has important implications for cooperation in multilingual
societies, which include many developing countries.