What I have written so far is based on my direct experience. Here are some other cases: You absolutely need to run program X, which only runs on English versio

What I have written so far is based on my direct experience. Here are some other cases: You absolutely need to run program X, which only runs on English version of Windows. (Developers of program X do not know nor care about internationalization). Therefore you run English version of Internet Explorer. Older versions of Internet Explorer only sends language(en) without sending locale(en-US). You speak English, live in England (or India), and don't want to get US page. You are bilingual (remember, lots of people outside US are bilingual), for example live in India and speak English and "mother tongue" very well. You prefer English for computer user interface, but prefer content in local languages.