Positive Past Plain form of Iku is Itta not iita?

Question

I thought when you get a type one verb ending with "ku" you replace it with ita. For example Kaku (to write) goes to Kaita. So I'm guessing Iku is an exception, does this happen with other verbs too ? Thanks ^^

Answer 1

Teachers and intermediate language learners regularly tell beginners that Japanese has only two irregular verbs (kuru and suru). This is not, strictly speaking, true.

As you've noted, 行く has the irregular formations 行った and 行って.

The negative of ある is ない... which is quite irregular

Imperatives often seem to have irregular forms, most notably くれ from くれる.

The conjugations of the honorific verbs (kudasai) can be considered as having their own pattern, or breaking the rules.

snailplane pointed out a few others 問う -> 問うた and 請う -> 請うた.

There are a few historical pronunciations that sometimes complicate this as well, such as the abbreviated する in 訳す or 達す. The -suru irregularity also extends to the -jiru variant in verbs like 禁じる.

(Note that wikipedia has a larger list)

Answer 2

Yes, 行く/iku is an exception to the rule. Specifically, its -te/-ta form is itte/itta. However, in most ways this verb is regular, so it usually does not get included in the list of exceptions, which is only two verbs long: する/suru, and 来る/kuru.

One other point of note is that 行く is sometimes pronounced "yuku," although this is slightly less common.

Answer 3

Here is how you derive the past tense for 行く (and the te-form, equivalently):

   past tense of /iku/  
== { past tense of X = continuative form of X + /ta/ }  
   /iki/ + /ta/  
== { generating a new word requires sound-changes }  
   repair(devoicing(/ikita/))  
== { /i/ and /u/ become devoiced/disappear in-between two devoiced consonants }  
   repair(/ikta/)  
== { normally, I-replacement repairs /k/+consonant; but here, gemination }  
   /itta/

Basically, it comes down to a devoiced vowel resulting in a consonant-consonant sequence, and that CC sequence getting repaired somehow.

For all other -ku verbs, e.g., /kaku/, we get /kakita/ => /kakta/ => /kaita/ , using I-replacement.

So the exception with /iku/ is that gemination repairs the /k/+C sequence instead of I-replacement.

That is the only exception I know which pertains to repairs, to directly answer your question (instead of the question "what words conjugate weird?").

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As to why this happens with 行く, I am not sure... in 徒然草 (1330-1332),

用有りて行きたりとも、其の事 果てなば、とく歸るべし

and even much more recently, in 不如帰 (~1898)

今まで知らぬ自由と楽しさのこのさきに待つとし思えば、父に別るる哀しさもいささか慰めらるる心地して、いそいそとして行きたるなり。

we indeed have proof it was, at least in writing, the continuative form plus the past(/perfect) morpheme, with no repairs. At some point, this changes, see こゝろ (1914):

私は早速先生のうちへ金を返しに行つた。

so this doesn't really help us figure out anything very much at all. I can't seem to track down anything useful here.

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I'd classify 問う and 請う as a different "exception" from 行く, because for whatever reason, a totally different sound change happened, from -ひた- to -ふた-. We can still see the older form here,

女に思ふやと問ひたりけれどいらへもせざりければ

思ふともいはずなりぬる時よりも増る方にて頼まるゝ哉

from 左近大將朝光 in the 後拾遺和歌集 (~1086). This -うた form is still around in the Osaka dialect and is used for the past tense and te-form regularly. It's not clear to me why there was this branch in pronunciation.