できる vs. potential form

[Melrudin]

What is the difference in meaning (if any) between:
日本語を話すことができる。and 日本語が話せる。
How do you differentiate when to use できる and when to use the potential form of the verb?

On a completely different topic. Why do you say 日本語が話せる。instead of 日本語を話せる。? Isn't 日本語 a direct object in this case?

[zengargoyle]

Melrudin wrote:
What is the difference in meaning (if any) between:
日本語を話すことができる。and 日本語が話せる。
How do you differentiate when to use できる and when to use the potential form of the verb?

the first is something like: i can do the action of speaking japanese.
and the second is the normal: i can speak japanese.

they mean pretty much the same thing.

this is a handy little cheat. you use the first form when
you don't remember how to conjugate the verb.

stolen from Japanese the Manga Way:

〜　こと　が　できる　koto ga dekiru
Another way to say "can/be able to" is to add the phrase koto ga dekiru/dekimasu to the dictionary form of a verb of any type. In this case koto ("thing") refers to the action described by the preceding verb, so it's literally like saying "can do the action of 〜". In actual usage, this "one size fits all" pattern can't quite be considered the same as the individualized "can/be able to" forms; there are sometimes subtle differences in nuance,­ and it can sound stiff. But for students still learning the language, it serves nicely in a pinch -- if you find yourself drawing a blank on how to make the individualized form.

[Melrudin]

Thanks for the info!

Could someone please answer my second question as to why you say 日本語が話せる instead of 日本語を話せる?

[Gaijinian]

The potential form indicates that something is possible and no actual action is taken. While the potential form remains a verb, since it is describing the state of something you must not use the direct object を as you have done with regular verbs. So, you use が。

[Melrudin]

Sorry, one more question:
So, if you were to add a subject to this sentence (instead of just having the subject being implied), would you say this?:
私が日本語が話せる。

[Schattenjedi]

Melrudin wrote:
Sorry, one more question:
So, if you were to add a subject to this sentence (instead of just having the subject being implied), would you say this?:
私が日本語が話せる。

no, 私は日本語が話せる。