A more formal way to express ability is to place こと が できる after the verb.
The word こと means situation, and is used to nominalize a verb. So by adding こと at the end of the plain form of a verb, we can turn it into a noun. In this way, the now nominalized verb can be used as the subject of the verb できる.
Sometimes the verb can be understood without mentioning it. In this case you can drop the verb.
|(I) can speak Japanese.||日本語 を 話すこと が できます。nihongo wo hanasukoto ga dekimasu.|
|(I) can speak Japanese.||日本語 が できます。nihongo ga dekimasu.|