These verbs:

Are all listed as 五段 verbs, but they don't follow the usual conjugation rules for them.
For example:

  • 命令形: いらっしゃる -> いらっしゃい, not いらっしゃれ
  • 連用形: Same as above, not いらっしゃり

Is there a separate name/classification for these types of verbs? Such as カ変 for 来る and サ変 for する.

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    And ござる, today in the form ございます.
    – user1478
    Commented Jun 9, 2014 at 8:08
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    It also bears noting that expected regular forms such as いらっしゃります or くださります did exist. C.f. 「一升ざけを 下さります 」 from the Tōkaidōchū Hizakurige, written in the early 1800s, or 「どなたもよふ いらっしゃりました 。きつひ御見かぎりで ござります 」 from the Kakutsū Yūshi by Utagawa Kunimasa, published in 1797. I suspect the modern forms arose as a kind of contraction or erosion common in oft-used words, such that the interstitial /-r-/ dropped out of the stem forms for the 連用形 and the 命令形. Commented Jun 9, 2014 at 18:18
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    My guess is that these are remnants of western dialect in the standard language from when the power shifted from West to East, similar to ありがとう,おはよう,ようこそ etc. instead of ありがたく,おはやく,よくこそ. But others probably know the details better than I do.
    – dainichi
    Commented Jun 10, 2014 at 1:33
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    I haven't found an explanation for why /r/ is elided only in those five verbs and only in certain constructions (e.g. with ます). Martin 1975 does note that the /r/ is retained in certain other constructions (see p.347).
    – user1478
    Commented Jun 10, 2014 at 2:58

2 Answers 2


I'd like to point out that those verbs also have "regular" forms of 連体形 and 命令形 even though not used quite often. As an extreme example, when making up the expression 連用中止法, they must be conjugated regularly to 連用形.

本日はご来場くださり、誠にありがとうございます。 "Thank you very much for coming today."

but 「本日はご来場ください、誠にありがとうございます」 makes no sense.

Therefore, people tend to think those verbs aren't very different from regular 五段 verbs, and try to account for their irregular forms by phonetic change (both forms) or sometimes by suppletion (only 命令形).

Phonetic change (reduction of R): kudasari > kudasai, kudasare > kudasae > kudasai

Suppletion: in this idea, ください is seen as short for the imperative expression くださいませ, which is a combination of the verb くださる in irregular 連用形 and the auxiliary verb ます in 命令形.


dainichi's comment in the OP is right.

These are left-overs of western dialect that are actually still used today:

Wants たい ー> とう (usually in the negative)

  • 行きたくないな・行きとうないな or 行きとうなかね

て/た forms of 「う」verbs

  • 何買ったの?・なんこうたと?

General Phonetic Shift ら行 sounds to い

  • それ何?・そいなん?
  • その人誰?・そん人だいね?
  • 二人は?・ふたいは?


  • 早く行きなさいよ!・はよう行きんしゃい!

With these it's easy to see how ありがとう and いらっしゃい came about.

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    It could help to explain a little further: as I understand it, ありがとう is from ありがたく. When the /k/ was lost, that gave ありがたう, and the regular sound change from /au/ to /oː/ resulted in ありがとう. So とう is not directly from たい.
    – user1478
    Commented Dec 28, 2014 at 4:10

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