生徒が分かる and 彼が見える and Intransitivity


I have been searching all internet and haven't found an "acceptable" answer
for it yet. I hope you guys can help me!

I was reading a text in the website KawaJapa about 分かる and the sentence
日本語が分かる. As a matter of fact, わかる is 自動詞 and means something like
"understandable" and not "to understand" which is transitive, so "Japanese is
understandable/comprehensible to me (私には)".

Following this line of thought, 見える would be the same: 富士山が見える, "Fuji-san is
visible". However, I was watching one lesson in Youtube from the channel
Nihongonomori about the uses of ために・ように and he gave two sentences that
confused me:

>   1. 生徒 **が** 分かるように、ゆっくり話します。
>   2. 彼 **が** 見えるように、手を振る。
>

I understand the meaning of both sentences, but if I analyze it based on what
was taught in Kawa Japa's website, then it doesn't make sense to me because
both sentences would sound like:

> "The students are understandable" **and** "he is visible"

When I know the sentences actually mean:

>   1. "so the students will understand..." and
>   2. "so he sees (me)..."
>

Shouldn't the sentences be, for example:

>   1. （テキストが）生徒 **に** 分かるように、ゆっくり話します。
>   2. （私が）彼 **に** 見えるように、手を振る。
>

So which sentence is more appropriate? Nihongonomori's

>   1. 生徒 **が** 分かるように、ゆっくり話します。
>   2. 彼 **が** 見えるように、手を振る。
>

or mine:

>   1. （テキストが）生徒 **に** 分かるように、ゆっくり話します。
>   2. （私が）彼 **に** 見えるように、手を振る。
>

I hope I could express my doubt in a clear way. Sorry for the big text.

みんな、教えてください。




生徒 **に** 分かるようにゆっくり話す and 生徒 **が** 分かるようにゆっくり話す are interchangeable. In short,
`X + が + potential-form` can both mean "X can do" and "one can do X; X is
doable". (Consider わかる as a kind of potential verb.) You have to infer the
correct interpretation from the context.

Unsurprisingly, when X is an animate object the sentence tends to mean "X can
do", whereas when X is an inanimate object the sentence tends to mean "X is
doable". It's usually not difficult to determine the correct meaning in one
way.

>   * このキノコは食べられます。 This mushroom is edible.
>   * 彼は食べられます。 He can eat (it). ([?]He is edible.)
>   * 星が見えます。 I can see stars.
>

Some sentences can be ambiguous if there were no context at all:

>   * 彼は殺せます。 (Someone) can kill him. / He can kill (someone).
>   * 彼が見えます。 I can see him. / He can see it (e.g., the stage).
>

