you get little credit for speaking swahili

From An Introduction to Sociolinguistics by Ronald Wardhaugh:

Monolingualism, that is, the ability to use only one language, is such a widely accepted norm in so many parts of the Western world that it is often assumed to be a world-wide phenomenon, to the extent that bilingual and multilingual individuals may appear to be ‘unusual.’ Indeed, we often have mixed feelings when we discover that someone we meet is fluent in several languages: perhaps a mixture of admiration and envy but also, occasionally, a feeling of superiority in that many such people are not ‘native’ to the culture in which we function. Such people are likely to be immigrants, visitors, or children of ‘mixed’ marriages and in that respect ‘marked’ in some way, and such marking is not always regarded favorably.

However, in many parts of the world an ability to speak more than one language is not at all remarkable. In fact, a monolingual individual would be regarded as a misfit, lacking an important skill in society, the skill of being able to interact freely with the speakers of other languages with whom regular contact is made in the ordinary business of living. In many parts of the world it is just a normal requirement of daily living that people speak several languages: perhaps one or more at home, another in the village, still another for purposes of trade, and yet another for contact with the outside world of wider social or political organization. These various languages are usually acquired naturally and unselfconsciously, and the shifts from one to another are made without hesitation.

There is a long history in certain Western societies of people actually ‘looking down’ on those who are bilingual. We give prestige to only a certain few classical languages (e.g., Greek and Latin) or modern languages of high culture (e.g., English, French, Italian, and German). You generally get little credit for speaking Swahili and, until recently at least, not much more for speaking Russian, Japanese, Arabic, or Chinese. Bilingualism is actually sometimes regarded as a problem in that many bilingual individuals tend to occupy rather low positions in society and knowledge of another language becomes associated with ‘inferiority’. Bilingualism is sometimes seen as a personal and social problem, not something that has strong positive connotations. One unfortunate consequence is that some Western societies go to great lengths to downgrade, even eradicate, the languages that immigrants bring with them while at the same time trying to teach foreign languages in schools. What is more, they have had much more success in doing the former than the latter.