tnw said:
wakaru means 'understand', shiru means 'know'. I think it's kind of similar to the difference between comprende and entiendo in spansih
Do you understand what I'm saying? 'itteiru koto wa wakarimasu ka'
Do you know what lotus root is 'renkon tte shitteimasu ka/gozonji desu ka?'
etc.
Well, a better way to translate わかる would be "to be clear". That's because
1) Unlike "understand", which can be a transitive verb (which means it requires a direct object), わかる requires が, not を. For example, you shouldn't say 「わけをわからない。」, but 「わけ
がわからない。」.
2) I find it easier to get the difference between わかる and しる if you keep "to be clear" in mind as the translation for わかる. The sentence I typed earlier translates as "I don't understand the reason (...why he did that, why it happened, etc.)", but if you were to translate it literally, it would go like this: "The reason isn't clear (to me)". Hard to confuse "to be clear" and "to know", isn't it? I guess you could say that "to be clear" is the clearer translation
.
Also, to use tnw's れんこん (lotus root) example, suppose someone tells you something about the lotus root. If they then ask you 「わかりますか。」, they're basically asking you if you understood what they've just said, the sentence as a whole. They ask you if what they said was clear. Now, if they tell you 「しっていますか。」, I guess they either want to know if you know the lotus root, or if you know the information they just gave you about it. Well, I'm not too sure about that last one, maybe they'd use the past tense, so if a j-gaffer thinks I'm wrong, I'll gladly stand corrected.
Anyway, I'm really sorry to insist, but, to those of you who have trouble understanding these concepts, just read
Making Sense of Japanese by Jay Rubin, it tackles all those issues. It's actually in that book that I found out the difference between the two verbs and why "to be clear" is a good way to "get" わかる.
@bigmit3737: "n desu" is also explained in the book I mentioned. To put it in a nutshell, you use it when speaking about a shared experience with someone, something you just noticed, or ascertained. It's kinda hard to explain, really. Say you see a friend reading a book, and they look engrossed (example from Rubin's book). If you tell them "omoshiroi desu ka", which means "Is it interesting?", you don't seem to have noticed how engrossed they look. On the other hand, if you tell them "omoshiroi
ndesu ka", which also means "Is it interesting?", it's a bit like saying "
you seem to enjoy this book", or "Is it interesting? Because you it sure looks like you're having a good time". Of course, I assume you can't completely get "n desu" unless you've encountered it countless times, but I think that's a good start. Also, please note that "no desu" is exactly the same thing, just a bit more polite. It's found in written language especially (not necessarily though). Also, as a general rule, remember that n(o) desu is used a lot more in spoken language than in written language.