I found this sentence while reading よだかの星:
よだかは、じっと目をつぶって考えました。(一たい僕は、なぜこうみんなにいやがられるのだろう。)
It seems pretty obvious that the parenthetical sentence is the Nightjar's internal monologue... but parenthesis aren't normally used like that in English
(English uses quotes or nothing for internal dialogue).
e.g.
The nightjar stopped to think, "Why am I hated by everyone like this?"
Why am I hated by everyone like this, the nightjar stopped to think.
And that got me thinking, (assuming my translation isn't way, way off...)
Are parenthesis () commonly used instead of 「」for internal dialogues in Japanese?
&
Are there any other notable differences between English & Japanese parenthesis?