“You’re in America; speak English” is a common statement in the United States. People belligerently make this pronouncement as our country approaches bilingualism, a common characteristic (at least; many countries are multilingual) of many other countries. Despite our country’s status as a world leader, our citizens have managed in some ways to remain insular, leading to the belief that one country means one language.
I met a man from Belgium once who told me that people in his area spoke five languages. With an area slightly greater than that of Maryland and population slightly smaller than that of Ohio, Belgium has two national languages, Flemish and French. The book and the movie “The Great Escape” demonstrate that one factor contributing to the prisoners’ chances at escape was the knowledge of languages other than English. I suspect that the size and proximity of European countries leads to bilingualism or multilingualism. Swiss people speak French, German, Italian, and Romansch. India has 15 or so official languages. The monolingualists would have a fit living there.