Note that the spell doesn't say "literally translates each individual word". It says that you "understand the literal meaning of what you hear".
A literal translation of "I'm under the weather" might be "A meteorological phenomenon is above me", but that is not the literal meaning of the phrase. The literal meaning is "I feel bad".
So the answer to the original question is that you would get the appropriate mandarin version of no for the question that was asked/the place in the sentence that the no was used.
My own view of comprehend languages would be that the results are as if reported to you by an extremely professional human translator who is trying to keep the emotional content neutral, and is also speaking to you as if you are an idiot. If someone says "no" in an exaggerated sarcastic manner, it would get reported as "yes". If someone says "oh, duh" it gets reported as "yes". If someone says "you'd best be on your way", it gets reported as "go away or you will be harmed".
In short: I don't think that you're going to get any hilarious mistranslations out of this spell. If you intend to build a game on language, you'd be best off either removing the spell or rewriting it to give literal word meanings, along with changing a lot of the rest of the game to rebalance investment in social skills and the like.