maryemily wrote:but, is this a choice? or is this related to the American Imperialism.......financial an technological superiority....?
Long before American economy got strong English was already used in some part of the world due to English colonization. Nowaday English is used more than other languages (well, second most language is used after Chinese) for international communication because British had and maybe still has many colonies that speak English, American has a strong economy that most of people want to do businesses with. Therefore, people speak English to be able to do business with them. If you have noticed, Spanish, French, and Chinese are used widely also. It's not just English.
Business is a hard-core competitive field, you have to do anything to satisfy your clients. If they want something in their language, you have to translate your products, ideas, memos, etc to their language. You can't just use English and tell them if they don't understand you, it's their problem. If you do that, you'll lose a business. My boyfriend works for a translation company. They try to translate everything in business to certain language that their clients demand. Thus, although America has a strong business, we still need people from other countries to do business with us and we have to do our best to satisfy them. We have people who can speak several languages or tools that the clients can understand the products in their own language. It makes them feel more comfortable.
For personal used, for an example, I speak Vietnamese, you speak your language, we both don't understand each other but if we learn a certain language in common, why don't we use that to communicate? It can be anything, don't have to be particularly English. If I knew French and so did you, we both could speak French to each other instead of English, right?
Overall, the choice is yours.