While playing League of Legends with some Japanese friends on the JP server, I noticed something interesting. Some of them use "ですが"in chat instead of the correct ”か” I asked them about it and they say that its just that they're lazy and type it the way they hear it, so is it similar to どうして usually being typed as どして because that's how Japanese people pronounce it in speech, differently from the way its written? i tried searching online for "desuga" and found no results, so its almost certainly incorrect, but native Japanese people are using it so...
どうして can indeed become どして in a hasty and slangy conversation/chat, but ですか never contracts to ですが. It's no shorter in the first place!
Both ～ですが and ～ですか are perfectly valid Japanese with completely different meanings.
- そうですか。 "Oh, is that so?" / "I see." / "Okay."
- どうしてですか。 "Why is it?"
- そうですが。 ≒ そうですけど。 "That's true, but..." / "Yes, but..." (sort of hedging)
- どうしてですが。 (typo. doesn't make sense.)
Sentence-end が/けど is asked and answered in several existing questions in this site. Please take a look at these.
- ですか -> for questioning. For ex: 安いですか Is it cheap?
- ですが -> for reasoning. For ex: 安いですが But it is cheap...
Japanese people tend to use the second one, as it is one form where they are asking indirectly to get better approach/ solution or to ask another thing behind that.