[KyleGoetz]

It may be a little late to chime in here, but to answer chryuop's implied question about using を・が・は in the 日本語○話せる context can be answered briefly:

There is a connotative difference between sentences using those three particles
日本語が話せる is the most generally "correct" form. It is neutral in connotation. It's merely a statement of fact.
日本語を話せる is correct, but sounds off a bit. I have heard natives say that this form sounds like it's emphasizing the language a bit, but I've no linguistic sources to back it up. I tend to avoid it because I'm not JLPT1 yet, so I don't consider myself qualified to answer authoritatively.
日本語は話せる is correct, but it definitely carries the extra implication of "I can speak Japanese [as opposed to some other language]." This is because は is used when making contrasting statements.

For example:
日本語は話せるが、英語は話せない。
I can speak Japanese, but I cannot speak English.

Of course, in all of our discussions, we've glossed over the other verb structure: 話すことができる.

A quick point:
Someone way earlier used 出来る. While this may be a correct use of kanji, various Japanese style guides (like Strunk & White's is for English) say that it is "better" to write できる without using the kanji. The sources don't say it's wrong; rather, that it's just better. This is like how it's not wrong to split infinitives in English, but it is better in many (most?) cases not to.

In summary, avoid using を in potential-form sentences unless you're absolutely confident you are right. I've spoken Japanese for years now, and I'm still not confident that I'm right. Stick to the は and が depending on the context I mentioned above, with the default being が unless you're contrasting.