I know the difference in meaning between the two: できます being "to be able to" or "can do", and わかります being "to understand how to" or "to know". I also know a simple sentence structure for both: "Person は Noun が (できます/わかります)" However, I can't understand which one to use in a sentence. Especially with the use of dictionary form verbs and こと in place of the noun.

I am trying to learn about this grammar point for a test and I just don't understand them. Here is an image of my notes so you see exactly what I'm seeing:


  • @DaveMG My guess is that she's come across both にほんごが できます and にほんごが わかります or similar phrases. In this sort of situation, they can be compared to one another.
    – user1478
    May 11, 2014 at 12:27
  • Hello, Meg! I'm going to edit out your bonus question because we like to keep it to one question per question here on the Japanese Language Stack Exchange. But please feel free to post it as a separate question as Dave M G has suggested. Thank you!
    – user1478
    May 11, 2014 at 12:35
  • I think できる is more general and can replace many verbs. わかる is 解する{かいする}ことができる here. はなしかた is the method to achieve your goal, はなすこと is the activity/skill itself, which doesn't imply a specific goal.
    – Yang Muye
    May 11, 2014 at 12:37
  • Sorry, yeah maybe it could. I don't really know how this website works.
    – Meg
    May 11, 2014 at 12:38
  • @Meg, it can take a little bit of time to get used to how JLU works, but you'll be fine. Just don't take it as a sign of having done anything wrong if people make or suggest edits. We just view every question an answer as a community effort in trying to make available helpful information in the clearest and best way possible. Hope you find the site helpful, and please ask lots of questions!
    – Questioner
    May 11, 2014 at 13:36

1 Answer 1


To keep things a little simple, I'll just extract one example of each case from all the ones you have on your sheet.


This is fairly straightforward. It says, "Sally understands Japanese."


Here, we're saying Sally has an ability for Japanese. A very direct, slightly clunky, translation might be something like, "Sally is Japanese-capable." You might want to see this answer about the implications of できる.

So, which would you choose? Well, just like when speaking English, saying someone understands Japanese, and that one is capable of Japanese, convey largely the same general idea, and in most daily conversation you probably won't go wrong exchanging one for the other. The difference is a matter of nuance. The first seems, to me, to lean towards the idea that if you speak Japanese to Sally, she'll understand you. The second seems to convey more that Sally can speak Japanese back to you.

Hope that helps.

  • So if I were to say "Sally can drive a car" it would be: 「サリさんは車のうんてんができます」right? But if I wanted to say "Sally understands how to drive a car" would it be: 「サリさんは車のうんてんすることが分かります」? Does this sound natural? Would it be easier or better to say one over the other? In this case using the できます sentence. I know that they both mean different things. To me the general meaning is similar and confusing when I have conversation.
    – Meg
    May 12, 2014 at 17:08
  • @Meg, Perhaps it would help if you were to tell me the difference in English between "understand" and "can do". The difference in Japanese is largely the same, so if you can explain how the concepts overlap in your mind in English, we might stand a better chance of figuring out why they are overlapping so much in Japanese for you. As for the addition of すること, you may want to see this answer.
    – Questioner
    May 13, 2014 at 2:53
  • @Meg You can say サリさんは車のうんてんができます, but you don't say サリさんは車のうんてんをすることがわかります.
    – user1016
    May 17, 2014 at 10:04

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