American expatriates, particularly those in business who are assigned abroad, often learn very little of the language and culture of the countries to which they are assigned. Some explanations of this phenomenon are offered based on observation of two U.S. communities in Tripoli, Libya, and Medan (Sumatra) from 1965 to 1973. First, the needs for learning the foreign language are minimal, and secondly, certain structures are imposed by the rules of the expatriate community, which constitutes a sub-culture of American society. Certain factors operate to maintain the sub-culture, such as (1) temporary residence status, (2) creation and maintenance of American institutions, (3) the extent of social and business contacts between the Americans and the host country nationals, (4) variation in usage of pidginized and standard English, and (5) differences in the influence of the local language on the language used by hosts to communicate with Americans. One reason for the development of the expatriate sub-culture and consequent minimal language learning may be fear of anomie, a problem comparable to marginality. If it can be shown by further study that behavior in the two expatriate communities also occurs in many other such communities, a functional reason could be given for limited linguistic acculturation in cases of temporary culture contact.