Here’s a question for you: Do you consider “wakaru” to be an active verb like “taberu”, “nomu”, or “suru”?
The truth is that “wakaru” is not an active verb. Likewise, “aru”, “iru” or “tsukareru” are not active verbs either. Can you tell these verbs are all the same type of verb? If you can, it should be easier for you to understand Japanese grammar. If you can’t, please accept that’s just the way it is.
The following sentences are very basic examples with active verbs:
Watashi wa soba o taberu. (I eat soba.)
Watashi wa ocha o nomu. (I drink tea.)
Watashi wa tennis o suru. (I play tennis.)However, unlike the verbs in those examples, “wakaru” is not an active verb, so we don’t say “watshi wa nihongo o wakaru.”
Nihongo ga wakaru.This is a grammatically orrect sentence. When you speak casually, you might say, “Nihongo wakaru?” “wakaru yo.” Or you may say, “kore wakatta?” “wakaranai.” The particles "o” and “ga” are not spoken so you can’t tell which one is omitted. It’s actually “ga” that is hidden there.
Mr. Jay Rubin, who has translated many of Haruki Murakami’s works, explains “wakaru” like this in his book Making Sense of Japanese:
People don't wakaru things; things themselves do wakaru: they "are clear" or they "are understandable."According to his explanation, “Nihongo ga wakaru” literally means “Japanese is clear/understandable.” When you think about it this way, it helps clarify why “nihongo o wakaru” is incorrect.
Based on that, you might ask, “How do you interpret the watashi wa in ‘watashi wa nihongo ga wakaru’?”
Watashi wa/niwa nihongo ga wakaru. ＝ As for me/To me, Japanese is understandable.Mr. Rubin also explains it this way.
Also, “wakaru” has many usages. While writing up until this point, I almost used “wakaru” many times, but I deliberately chose other verbs each time. It’s possible to replace the verbs marked in pink above with “wakaru”.
Let’s have a look at the definition of “wakaru” in a Japanese dictionary.
1) to understand
example) Wake ga wakaranai. (It doesn't make sense.)
example) Anata no iitai koto wa yoku wakaru. (What you mean is understandable.)
2) to prove a fact
example) Hannin no mimoto ga wakaru (find out the criminal's identity.)
example) Mondai no kotae ga wakaru (discover the answer to the question.)It’s clear that “wakaru” doesn’t mean only “understandable” or “understand”. In addition to the examples above, it can also sometimes be “learn” or “realize”.
Lastly, since “wakaru” is not an active verb, it doesn’t have a potential form. "Wakareru” doesn’t exist. When you want to say “I can understand”, use “rikai dekiru” instead. “Rikai” means understanding. (However, "wakaru" itself sometimes means "I can understand".)
Wakaru no tsukaikata ga wakarimashita ka? (Did you figure out how to use “wakaru”?)
Minasan, JLPT gambatte kudasai !!