If I was to say : "Do you understand me?", would it be as simple as "Förstår du mig?"
Maybe it is related to the German "verstehen", "stehen" means stand, and "ver-" is a very common prefix on verbs especially.
i thought i was "you understand?" does it become "do you" when it just makes the sentence make more sense?
Yes, it's because that's the way English prefers to ask it. We try to avoid phrasing questions as just a normal sentence with a pitch rise at the end.
"Understand?" and "you understand?" are phrases used quite often in England, though "do you understand" is a more formal way of addressing one person as the question seems to imply. The full phrase comes across as more dictative or authoritative.
Some English verbs aren't normally used in the progressive form. This tends to be the case for verbs with 'stative' meaning, i.e. they're not really describing an action/someone doing something, more a state/situation.
in english (although it is maybe not formally correct) we say "don't you understand?" sometimes instead of "do you understand?"
could this be a correct translation? I kept wanting to type the negated question here, as a native english speaker.