It seems rather that it is the other way around - the US dominated (and still does) the computer industry, and so ASCII, the English-centered character set, became the standard. ASCII is good enough (you might lose some accents on certain characters in certain words and such, but nothing much) for English but has no consideration for any other characters that might be used in other languages.

If Turkey was the dominant country in IT, I don't see why they wouldn't do the same thing only for their own alphabet; include all the characters of their alphabet (latin alphabet plus a few more), plus some more common characters used in math etc.