Some things that I have noted since being here that probably won't appear in any sort of travel guide:
1. Later -this means the person will get on said task immediately and be back before you have time to finish changing your t-shirt
2. Later Later - this is slightly longer than later...could be 15 minutes, could be an hour or two. It's hard to say.
3. I know - said once, it generally means that they do in fact comprehend whatever it is that is being said
4. I know I know - the more times that "I know" is said, the more you can be assured that they really have no idea what you just said. Generally though, the individual will be remembering the sentence and translating it later if possible.