The previous verb paradigms were fairly regular, even in the spots where particular types deviated from the norm. Memorizing the different conjugations is not terribly difficult, and there aren't a lot of conjugations possible. Almost every verb in Japanese follows one of the two –る or –う paradigms.
But even Japanese has irregular verbs. Most books say that there are only two irregular verbs in all of Japanese: する and 来る (くる). These two must be memorized separately from all the others. However, even they make sense in their own way once analyzed closely.
First we'll look at 来る (くる), "to come".
|来る (くる)||infinitive||"come", "will come" or "comes [often, ...]"|
|来 (き)||root||add –ます; note that –やすい is not used|
|来て (きて)||gerund||"come and [...]"|
|来た (きた)||past tense||"came"|
|来たら (きたら)||conditional||"if/once someone comes", some sense of 'when'|
|来たり (きたり)||alternative||"do things like come"|
|来れば (くれば)||conditional||"if someone comes", no sense of 'when'|
|来よう (こよう)||volitional||"let's come" (has nothing to do with orgasm, sorry)|
|来い (こい)||imperative||"come!", rude|
|来ない (こない)||negative||"won't come" or "doesn't come [often, ...]|
|来られる (こられる)||potential||"can come"|
|来させる (こさせる)||causative||"make someone come"|
|来られる (こられる)||passive||"come via X" (FIXME: awful example)|
|来させられる (こさせられる)||causative passive||"be made to come [by someone]"|
Now let's consider する, "to do".
|する||infinitive||"do", "will do" or "does [often, ...]"|
|し||root||add –ます or –やすい|
|して||gerund||"does X and [...]"|
|したら||conditional||"if/once someone does", some sense of 'when'|
|したり||alternative||"do things like doing"|
|すれば||conditional||"if someone does", no sense of 'when'|
|しない||negative||"won't do" or "doesn't do [often, ...]|
|できる (せる)||potential||"can do", usually できる|
|させる||causative||"make someone do"|
|させられる||causative passive||"be made to do [by someone]"|
A little trick to remember suru is that many of the conjugations match what you would get if you conjugated a lone verb 'す'. It works somewhat like like はなす, eg はなした → した, はなせる → せる, はなさせる → させる.
Look closely at the potential conjugation of する above. It says でき る, "can do". But せる is also shown. Usually できる is used to indicate the potentiality of doing something, but sometimes せる is used such as in the sentence "愛するひと" (あい する ひと), "someone I can love".
There are actually a number of other verbs which are also irregular in Japanese, although traditionally textbooks and grammar books prefer to ignore them or pretend that they aren't irregular. These irregulars are all –る verbs which have certain peculiarities about them. A list of these verbs is given below.
|在る (ある)||"to be"|
|行く (いく)||"to go"|
|なさる||"to do" (honorific)|
|下さる (くださる)||"to give" (honorific)|
|仰る (おっしゃる)||"to say" (honorific)|
|御座る (ござる)||"to be" (honorific)|
|いらっしゃる||"to be" (honorific)|
The first two are very basic verbs which tend to be irregular in nearly all human languages, Japanese being no exception. The latter five are honorific verbs used only in polite speech. Their irregularities are all found only in the root form and actually represent verb conjugation paradigms once active in old Japanese but now preserved in these verbs mostly due to their use in certain set phrases such as お早う御座います (おはよう ございます, "good morning", lit. "it is early") and 御免なさい (ごめん なさい, "excuse me").
The verb 在る (ある, "to be") is only irregular in one form, the negative. In this conjugation it is written ない. Astute readers may note that ない is also the suffix added to all negative conjugations of other verbs. In this one case there just isn't a verb to add it to. In the negative of the polite –ます form however it is ありません.
The verb 行く (いく, "to go") varies from its related –く verbs in that instead of the expected いいて, いいた, いいたら, いいたり, it is actually いって, いった, いったら, いったり.
The other five verbs are distinct in their root forms, ie the forms which attach –ます. Instead of forming a –り to attach –ます, e.g. *なります, they form an –い. The following table should clarify this.
|下さる (くださる)||→||下さい (ください)|
|仰る (おっしゃる)||→||仰い (おっしゃい)|
|御座る (ござる)||→||御座い (ござい)|
Note that 御座る (ござる, "to be") and いらっしゃる ("to be") are typically used in their polite –ます forms, giving what is commonly called (in English) the 'superpolite' form: 御座います (ございます), いらっしゃいます. It's good to remember the non-superpolite versions of these verbs, but don't expect to ever use them. But watch Ruroni Kenshin for a good example of using で御座る.