日本語ができます or 日本語が話せます?
I've never actually had any particular lesson about this, but I always have seen people saying "日本語ができます", I actually saw in a Japanese book that this is an abbreviation of "日本語ことができます". However, I've always seen English-Japanese speakers saying "日本語が話せます". I already know that "話せます" is the potential polite form of 話す, but, is this actually a usual and natural way to say it or is it a translation thing? Which one is more widely used? Honestly, I've never seen "日本語が話せます" in real context before...