Knowing and learning
Verbs for what you know: understand, know, remember, forget, and study — the ones a learner uses about themselves in every exchange.
wakaru
polite wakarimasuunderstand; know; get it
分かる わかる 分かります
Understanding or being able to tell (wakaru?, wakaranai), with the thing understood marked by ga, and wakatta doubles as 'got it / OK'.
kono kotoba wakaru?
Do you understand this word?
この言葉分かる?
kono kotoba wa wakarimasu ka?
Do you understand this word?
この言葉は分かりますか?
wakatteru = 'I know already', which can sound irritated.
Learn alongside: shitteru
shitteru
polite shittemasuknow (be aware of)
知ってる しってる 知ってます
Having a piece of information or knowing a person or place, where the positive is always shitteru and the negative always shiranai (never *shittenai).
kono kotoba shitteru?
Do you know this word?
この言葉知ってる?
kono kotoba wa shittemasu ka?
Do you know this word?
この言葉は知ってますか?
Polite shirimasen can sound like 'not my business'; wakarimasen is the safe polite 'I don't know'.
oboeru
polite oboemasuremember; memorise
覚える おぼえる 覚えます
Getting something into memory (oboeru) and still having it (oboeteru / oboetenai), so 'do you remember?' is always oboeteru?
ano hito no namae oboeteru?
Do you remember that person's name?
あの人の名前覚えてる?
ano hito no namae o oboetemasu ka?
Do you remember that person's name?
あの人の名前を覚えてますか?
Bare oboeru means 'memorise'; remembering now is oboeteru, and 'oh, now I remember!' is omoidashita, not oboeta.
Learn first: -teru
wasureru
polite wasuremasuforget; leave behind
忘れる わすれる 忘れます
Forgetting names, facts and plans and leaving things behind, mostly as wasureta / wasurechatta, plus the reminder wasurenaide ne (don't forget) and a, wasureteta (oh, I'd forgotten).
ano hito no namae wasureta.
I forgot that person's name.
あの人の名前忘れた。
ano hito no namae o wasuremashita.
I've forgotten that person's name.
あの人の名前を忘れました。
Leaving an item behind is also wasureru: kasa wasureta.
benkyou suru
polite benkyou shimasustudy
勉強する べんきょうする 勉強します
Says you study something, with o often dropped in casual speech (nihongo benkyou shiteru); benkyou ni naru (that's good to know) is the stock reply to an explanation.
nihongo benkyou shiteru n da.
I'm studying Japanese.
日本語勉強してるんだ。
nihongo o benkyou shiteru n desu.
I'm studying Japanese.
日本語を勉強してるんです。
benkyou ni narimashita thanks someone for teaching you something.