Origin of -aru verbs: いらっしゃる、おっしゃる、くださる、なさる

Question

I think all of the mentioned verbs are in the same class, because they all inflect irregularly in the same way: -aimasu for the polite form rather than -arimasu.

My question is how these verbs were formed. My guess is there is some base verb which was connected to aru and then underwent some sort of devoicing and 音便.

For example, does くださる originate from 下す + 在る?

If this guess is correct, does this 在る have some semantic meaning? (There seems to be a large chance that it's used to make things more polite, since these are all 敬語.)

Answer 1

Let's look at each of these one-by-one:

• いらっしゃる is a contraction of 入らせらる, which is the 文語 form of 入らせられる, a lexicalized combination of (入る→入ら) + (す→せ) + られる.

• おっしゃる is a contraction of おおせある, which appears to be the simple combination of 仰す→仰せ and 有る (not 在る).

• くださる appears to come from (下す→下さ) + る.

• I'm not sure about なさる, but it seems likely that 為{な}さる is related to 為{な}す. It looks like (為す→為さ） + る, but since I'm making a guess, I'm probably wrong :-)

If my guess about なさる is right, then なさる and くださる share the morpheme る, which I suppose functions to make both of them honorific. The morpheme られる in いらっしゃる is not the same, but in this case probably has a similar function to る; the linked definitions for both る and られる say they can express 尊敬. The 有る in 仰せ有る also has an honorific sense--see 〔2〕-【5】 in 大辞林. In that sense, it says 有る attaches to the 連用形 of a verb, and 仰せ is exactly that, so it fits.

So I guess in all four, a suffix adds 尊敬 to the word, but the suffix in question isn't ある in each word. Rather, it's られる, ある, る, and maybe る if my guess is right.

Answer 2

I would add a comment to the above answer, but it appears I need "reputation" to do so. Anyways, for the last two words, look here http://archive.org/stream/historicalgramma00sansuoft#page/162/mode/2up

[on the classical passive form] (3) to form honorific verbs An important feature of the passive forms is their frequent use in an honorific sense. [...] The usage is a well-established one, and is common in the modern language, both written and colloquial. E.g. [...] The polite forms nasaru, 'to do', kudasaru, 'to condescend', irassharu, 'to be present' (=irase-raru), &c., also illustrate this honorific usage.

Note that the above resource identifies いらっしゃる with 居らっしゃる instead of 入らっしゃる. The historical spelling is ゐる for 居る, and いる for 入る, yet I find no mention of *ゐらっしゃる anywhere, so this lends credibility that it is not derived from 居らっしゃる.

Also, る is the classical passive/potential suffix. If you're interested, I suggest you start reading the above mentioned book from page 158 onwards: http://archive.org/stream/historicalgramma00sansuoft#page/158/mode/2up