Are there verbs that end with ず,づ, ふ, ぷ, しゅう, ちゅう and じゅう? Why not?

Question

I noticed that verb ending syllables cover all of -u syllables (る,く,ぐ,す,つ etc) except ず,づ, ふ, ぷ, しゅう, ちゅう and じゅう.

I suspect that ず is reserved for the negative conjugation thus no plain form verb is allowed. しゅう, ちゅう and じゅう were mostly reserved for on-yomi pronunciation, I think, so no verbs for them either.

Not sure about づ.

ふ and ぷ is a curious case because there are verbs that end with ぶ but not the other two.

I'm not saying that there should always be verbs that cover each of the -u syllables but I'm just curious why there are no verbs that end with some of them. Maybe there are some historical reasons behind the gap?

Answer 1

Actually, there were verbs ending in some of the syllables you listed, but they have changed to different forms in modern Japanese.

• ず

  Most verbs ending in ず were サ変 verbs; they became regularised as 〜じる verbs, e.g. 感じる、生じる、命じる etc. Note that these examples are all derived from Chinese words which originally had nasal endings. Sometimes these also show up with the ending 〜ずる instead of 〜じる.

• づ

  There were a few verbs ending in づ, but the ones I know are all 下二段 verbs; in modern Japanese they are the 一段 verbs ending in 〜でる, e.g. 出る（←いづ）、撫でる（←なづ）、愛でる（←めづ） etc.

• ふ

  Most of these verbs were 四段 verbs became 五段 verbs in modern Japanese. Fairly early on (early 2nd millennium if I remember correctly), /f/ between vowels became /w/; of course, /wu/ simplified to /u/, and later, the diphthongs /au iu eu ou/ shifted as well. But here history becomes a bit messy. If all the sound changes were regular, the verb 笑う we know today should have become わろう—indeed, if I'm not mistaken there is evidence that it was that for a while, in the Nippo Jisho (日葡辞書). Yet, with the exception of certain forms in western dialects (e.g. 笑うた), most of these 四段 verbs ending in ふ just became the obvious 五段 verbs ending in う. This is probably due to analogical reformation. (However, 言う is still frequently pronounced as if it were ゆう.)

  A few verbs ending in ふ were 二段 verbs; these became 一段 verbs in modern Japanese. Examples: 変える（←かふ）、終える（←をふ）、強いる（←しふ） etc.

• ぷ

  Even earlier on (1st millennium) in Japanese, /p/ between vowels became /f/. So it's not very surprising that /p/ is rare in native vocabulary. The Japanese Wikipedia has some discussion about this: see は行 and ハ行転呼.

• しゅう、ちゅう、じゅう

  Syllables like しゃ、しゅ、しょ were not originally present in Japanese–words with these sounds are either onomatopoeic, imported from foreign languages (including Chinese), or have undergone some sound change.

  Allowing for sound change, any 五段 verbs that end in しゅう、ちゅう、じゅう must have developed from verbs ending in しふ、ちふ、じふ, but because of the analogical reformation I mentioned earlier, these would now be verbs ending in しう、ちう、じう. But looking at the dictionary there are very few of these verbs—in fact, I can only find one (癈ふ as a 四段 verb), and it's listed as an alternative for 癈ふ (as a 上二段 verb). This is something I don't have an explanation for.

Answer 2

I agree with Ignacio. You can also find some old words that ended with づ. I think--am actually pretty sure--the chances were for pronunciation. As you know, much of Japanese's pronunciation guidelines were derived from Chinese language. Well, there are also derivatives of Korean words and original Japanese words, and there is thought to be some impact from other parts of the world as well, such as Russia, due to the grammatical structures.

Anyway, Chinese pronunciation is fine and well varied when compared to hiragana. People had different ways of pronouncing things. It was difficult to adapt the language, and the language was difficult to speak. Hiragana didn't cover all of the possible character pronunciations Chinese language accommodated. Also, Japanese language was kind of bulky, when you stack the influx from multiple countries on top of the complicated grammar. Some reforms were made to deal with all of these issues. The number of kanji taught to school children, the pronunciation of words, the way verbs were conjugated, standardization of characters, etc.--all done in Japanese language reforms.