why English is spoken in so many countries?

English has made its way into a lot of other countries because there are so many Americans who travel overseas or purchase foreign goods (foreign to us that is). At least, that’s the way I see it. When you have to deal with rounds of English speaking tourists all the time or even English speaking people that move to/retire in your country, you learn the language to accommodate them because they help your economy. In America, we do the same thing for Spanish. Though it is not our native language, we have enough Mexican immigrants to force us to have Spanish speakers throughout the country. It’s a matter of adjustment to fit a growing demand.

English is so prevalent not because of American travel, which has only been occurring in any great significance for 50 or 60 years, but because a very large portion of the world was ruled by the British Empire for several hundred years, and those that were not under its direct control was held in the grip of English trade. The result was that if you wanted to have any contact whatsoever with the governments or economies of anyone else in the world, learning English was quite literally your only option.