What is the transitivity of potential forms of verbs? [jisho.org](https://jisho.org) states that できる is intransitive. Are all potential form verbs intransitive? They do use the が particle instead of を, but I’ve also heard that they could use を so I’m not sure.
Along with that, can direct objects exist in a sentence without the を particle? For example, in the following sentence:
リンゴは弟に食べられた。
食べる has been changed to passive form and the を particle isn’t used. Is リンゴ still a direct object?
4 comments
りんごは弟に食べられた is a passive sentence.
弟はリンゴが・を食べられた is correct for potential.
I’m assuming (a link would’ve been helpful) the できる entry was for the (stand-alone) verb that means “to be doable/possible.” ~~That verb works like 好き in that you need が for what would be the direct object of the verb in English~~. With this verb, you mark what would be its direct object with が.
I can play (do) baseball becomes 私は**野球が**できる
This has very little to do with the potential form. The potential form of a verb is same in transitivity as the dictionary form. Conjugations don’t change transitivity. The English verb “present” is transitive in the non-past tense. So are its past form “presented my thesis,” its gerund “presenting my thesis,” and its infinitive “to present my thesis.”
You might want to look up the 「ΑはBがC」construction. This が is the が in your question. A potential form can take the place of C in this construction. The specific word できる always shows up in the form of this construction (with optional omitting of A and B, of course).
As for more general potential forms, they can take either が or を. A quick google search of 英語が話せる led me to two different sites, one named
英語を話せるようになるのは意外と簡単？！
and another named
英語が話せる人の共通点！
Clickbaity titles aside, you see my point.
A dictionary of basic Japanese grammar states that when a potential form uses を, it implies a higher degree of active volition than when it uses が.
In addition, keep in mind that を can also indicate the space in/on/through/across/… which one is traveling. This usage of を has nothing to do with direct objects and hence has nothing to do with transitivity, and thus stays as を under potential form. e.g. この道を一人で歩けない
Yes, we can use direct objects as subjects (some) and topics (all?) in Japanese, so it can appear with が and は. Most common are emotions and abilities, which are said as リンゴが食べたい.
I don’t know if it’s grammatical to use を with potential forms in modern time, but many people do so. Basically that we are talking about is common in many languages. Comparing to many volition actions like “chasing”, emotions and abilities aren’t under our control. We can’t decide that we will like and what we won’t. It’s likeable for us by itself. But comparing to completely intransitive actions like “sleeping”, we still have an object of action. So in some languages emotions and abilities are transitive and in some languages are intransitive.
The tricky point is that abilities can be learned. Technically we can’t guarantee that someone will get specific skill, person can attempt to do so and see the result at the end. But, for example, when we talk about foreign languages, billions of people do so successfully and there is no way not to learn it with enough practice. So many people decide to use を when it’s volition decision to do so and が when it’s something that we can do passively/naturally.