〜られる or 〜ことができる?

The potential form says you are *able* to do something. The object usually takes が rather than を — 日本語が話せます, not 日本語を話せます — because the sentence is really about what is possible, not what you act on.

In casual speech 一段 verbs often drop the ら (食べられる → 食べれる). You will hear it constantly; it is still marked wrong on the exam.

A more formal alternative to the potential form, common in writing, signs and announcements. ここで切符を買うことができます.

Same meaning as 買えます, but heavier — in conversation the potential form is what people use.

Expresses ability or possibility in a slightly formal way.