Not all questions start with Wh- words, so why don't we start a question with a question mark to make it more obvious that it is actually a question?
For instance, when I'm reading a book which has a long interrogative sentence at the bottom of the right-hand page, it often isn't until I turn to the next page that I realize it is a question.
Not that this represents too much of a problem, but from a beginner's perspective it must make it harder to interpret the words of the sentence in the correct context.
Similarly, why don't we start exclamatory sentences with an exclamation mark?
I know this is a trivial question, but I'm wondering whether some kind of historical or colonial/imperial decision might explain the absence of these marks in the situations I describe.
P.S. I am a student programmer, so pardon my ignorance / funniness