Let's say you're falling to your death, and you yell:



助けて！
tasukete!
Help me!

When someone saves you, you can say:



助かった。
tasukatta.
You're a life-saver. / Thanks.
(Literally, "(I was) saved.")

Now, we DON'T say:

助けた
tasuketa.
Because that would sound like we're saying, "I saved you:"

助かる (tasukaru) is a 自動詞 (jidoushi), an "intransitive verb."

But 助ける (tasukeru) is a 他動詞 (tadoushi), a "transitive verb."

So why do we use an intransitive verb in this situation?

I have no idea. T_T

But we do.

Maybe it's because the "focus" of "You're a life-saver," in Japanese, is more like "I was saved (by you)," and this is expressed by the intransitive 助かる (tasukaru).

If the person who did the saving was talking, they could say 助けた (tasuketa), "I saved you," but that sounds kind of rude, don't you think?

With a transitive verb, the focus is on the one performing the action. This is why we can say 助けて！ (tasukete), "Please help me!" In other words, "You please help me."

We can't however, say 助かって (tasukatte), because it cannot be a request. Instead, it sounds like, "(I) was saved, and..."

To make things even more confusing, in addition to 助かった (tasukatta) for "You're a life-saver // You saved me // I owe you," you could also say:

ありがとう。助けになったよ。
arigatou. tasuke ni natta yo.
Thanks. You've been a big help.
(Literally, uh... "Thank you. (What you did) became saving?")
(Note: It would sound weird to say this for someone saving your life. More like the type of thing you'd say when someone helped you out at the office, at school, etc.)

The bad news: This is still really confusing, right?

The good news: I learned this naturally without really studying it. I just heard people saying these verbs in different contexts and sort of figured this out. You should be able to learn it much more quickly than I did now. ^_^

Transitive and intransitive verbs are really confusing in Japanese, so don't worry if it takes a while to learn them. Once you do, though, your ninja powers will increase!

Bonus Phrases:

どうか助かってください。
どうか　たすかって　ください。
Please let him be okay.
Literally: somehow or other + save + please
Note: Pretty much the only time you'll see 助かって instead of 助けて.