Way to fly off the handle, normann. Even if it can't be substantiated that English is an official language for the Internet overall, at the very least is a very common secondary language in many countries. When I was in school, English and French were considered the dominant global languages due to the number of countries in which they were the dominant or official language.
Some forums require that everybody post in a specific language so that it can be effectively moderated. Some countries are extremely demanding about how quickly complaints about posts that offend certain laws are handled, and that requires that the posts can be understood by the moderators. Ultimately, I wonder how many of the developers and users that frequent the forum can read in multiple non-programming languages, let alone Turkish?