Conjugation of する verbs like 発する


I'm trying to understand how to conjugate verbs like 「発する」, 「属する」, 「察する」 and
the like.

In a book I found 「発せられる」, which I think is the potential form of 「発する」, but
it doesn't seem to follow the usual rules, so I was wondering: how about
causative, passive and other forms? Does it matter if the verb has a っ (はっする)
or not (ぞくする)?

I tried checking online, but I found both 「発せられる」 and 「発できる」 as potential (and
IME recognize both), but I won't even be sure about how to read the latter
(はっできる? はつできる? IME recognize the former) so I'm kind at a loss here.




As [this answer](https://japanese.stackexchange.com/a/46878/5010) says, these
"special suru-verbs" are tricky and unstable. They conjugate sometimes like a
suru-verb and sometimes like a godan-verb. However, they never turn to dekiru-
form like normal suru-verbs do. That is, we can say 運転できる or 勉強できる but not
属できる nor 発できる.

One workaround is to conjugate them as godan verbs (発せる, 属せる, 察せる). However,
as the linked answer says, tendency to conjugate as a godan verb depends on
the verb. Among these three, I think 属せる is completely fine, but I feel 察せる is
less common, and 発せる is unnatural (although understandable). Likewise, I feel
属さない/属そう is fine but 発さない/発そう/察さない/察そう are unnatural if not wrong. This means
属す(る) is more godan-like and 発する is more suru-verb-like in my mind.

How about 発せられる? This looks as if there were an ichidan verb 発せる, but actually
せられる is an [archaic passive
form](https://japanese.stackexchange.com/q/59114/5010) (e.g., 罰せられる is "to be
punished" and 熱せられる is "to be heated"). 発せられる has a passive meaning ("to be
emitted"), but from my experience せられる rarely has a potential meaning.

Fortunately, there is one safe approach that works regardless of the type of
the special suru-verb. Simply **use することができる** and say 発することができる, 属することができる
and 察することができる! I think even native speakers often (unconsciously) take this
approach when they are unsure.

Another approach is to use し得る and say 発し得る, etc., but this tends to mean
"possibly ～" rather than "is able to ～", and sounds literary and stiff.

Related: [What are the valid potential forms of special "suru"
verbs?](https://japanese.stackexchange.com/q/5113/5010)




As [this answer](https://japanese.stackexchange.com/a/46878/5010) says, these
"special suru-verbs" are tricky and unstable. They conjugate sometimes like a
suru-verb and sometimes like a godan-verb. However, they never turn to dekiru-
form like normal suru-verbs do. That is, we can say 運転できる or 勉強できる but not
属できる nor 発できる.

One workaround is to conjugate them as godan verbs (発せる, 属せる, 察せる). However,
as the linked answer says, tendency to conjugate as a godan verb depends on
the verb. Among these three, I think 属せる is completely fine, but I feel 察せる is
less common, and 発せる is unnatural (although understandable). Likewise, I feel
属さない/属そう is fine but 発さない/発そう/察さない/察そう are unnatural if not wrong. This means
属す(る) is more godan-like and 発する is more suru-verb-like in my mind.

How about 発せられる? This looks as if there were an ichidan verb 発せる, but actually
せられる is an [archaic passive
form](https://japanese.stackexchange.com/q/59114/5010) (e.g., 罰せられる is "to be
punished" and 熱せられる is "to be heated"). 発せられる has a passive meaning ("to be
emitted"), but from my experience せられる rarely has a potential meaning.

Fortunately, there is one safe approach that works regardless of the type of
the special suru-verb. Simply **use することができる** and say 発することができる, 属することができる
and 察することができる! I think even native speakers often (unconsciously) take this
approach when they are unsure.

Another approach is to use し得る and say 発し得る, etc., but this tends to mean
"possibly ～" rather than "is able to ～", and sounds literary and stiff.

Related: [What are the valid potential forms of special "suru"
verbs?](https://japanese.stackexchange.com/q/5113/5010)

