I know I need to answer in the same way regardless of questions are positive or negative in English.
For example, when I didn't go to work yesterday,
Q. Didn't you go to work yesterday? (Did you go to work yesterday?)
A. No I didn't.
I am still taking time when answering negative questions in the real life, because in the language I was using before, it was deferent way. If I say yes to negative questions, it means I agree asker's negative questions. Anyway, I have been adapting to the English way to answer.
But what confuses me is that I meet those kind of native speakers who answer "Yeah." to the negative questions.
For example,
Q. You don't want to go?
A. Yeah. (When he/she doesn't want to go.)
There have been many of native English speaker answering like this. So I am wondering if there is a difference between 'yes' and 'yeah'.
Best Answer
These sorts of questions (asked to reply in the affirmative to a negative) are fundamentally confusing, and can't be answered yes or no without adding to the confusion.
If someone says "You don't want to go?", it's like saying "Is is true that the negative is the case?". An answer yes or no could be replying to "is it true" or replying to the negative.
So, both "yes" and "no" are poor answers to a poor question, if we're judging communications on their quality and comprehensibility.
It's best to answer these sort of questions in more depth - you can still use yes or no eg
Q:"You don't want to go?"
A:"No, I don't want to go", or, more simply "I don't want to go".
In both cases, the questioner has been left in no doubt about the answer to their question.