Spoke

[themonk]

What is the difference between:
nihongu→nihongo
wagarimasu→wakarimasu

[Hyperworm]

nihongu→nihongo
wagarimasu→wakarimasu

Your question about 'o' vs. 'ga' is a good one.
There are a rare few verbs that tend to take 'ga' where we as English speakers would expect 'o'.
'wakaru' (i.e. 'wakarimasu') is one of them.
I've read it explained as "in fact, wakaru doesn't mean 'to understand'; it actually means '(of meaning etc) to be clear (to sb.)', 'to be understandable (to sb.)".

Then you'd have
nihongo ga wakarimasu ka = Is Japanese understandable (to you)?

It's probably easier just to remember that wakarimasu uses ga and not worry about the details, though; the above translation gives the impression that the original Japanese is clunky, which it's not. "[x] ga wakarimasu" is a very natural way of saying "I understand [x]" in Japanese, so it's best translated with something equally natural in English.

I don't think 'o' vs 'ga' comes up all that often.

[themonk]

Thank you