For me, "understanding" and "comprehension" are mostly synonymous - they usually mean the same thing (with a little nuance (: of course ). But, use of the word "comprehension" is less common in conversation, and it is usually reserved for describing how well someone knows a subject matter like mathematics or a foreign language, for instance "My English listening comprehension needs work. I'm not good enough at it yet!" - (Sounds good) "My English understanding needs work." - (Sounds a bit awkward) If someone has good listening comprehension, it means that they usually understand what others are saying VERY well. I can understand what someone is saying to me - I hear their words and I can process their meaning. But, if I comprehend what someone is saying to me, it usually indicates that you have a deeper or more thorough understanding of what they said. You can "understand" what someone says, but you can "comprehend" the other meanings, consequences, or importance of their words.

You get the basic meanings from the dictionary etc, but I think you have to learn nuances from interaction with native speakers. So much of the nuances of communication come from the context, tone of voice and body language, all operating within a framework of cultural conventions. Perhaps you can get this kind of information from film, TV etc, but to my mind that would be much more difficult.

Hello, Jihye I'm an English learner as well. I use several tools to grasp the English expression, such as an English-English dictionary, an English-Chinese dictionary, a Thesaurus, a phrasal verb and collocation dictionary. What so-called a good dictionary to me is a dictionary of which provides a lot of examples. The more sentences I read, the more it will build up the sense of English expression in my brain. Last but not least, read a lot of good books and highlight the frequent words you'd like to use. And, enjoy your time. Your effort will pay off. Hope the tips help you, Tere

You can look at the history of words here: etymonline.com This will give you some ideas about how we perceive words in the modern day. For example, "understanding" has an Old English origin, whereas "comprehension" has a Latin origin. This explains some of the nuances that Trace described in her answer.