Japanese consonant and vowel verbs
The Japanese language has two types of regular verbs that involve the stem, and can be referred to as Japanese consonant and vowel verbs.
The two groups of verbs are:
- consonant-stem, godan-katsuyō (五段活用?, "5-class conjugation") , Group I, or -u verbs; and
- vowel-stem, ichidan-katsuyō (一段活用?, "1-class conjugation") , Group II, or -ru verbs.
Most verbs are consonant-stem, but vowel-stem verbs are also common, hence the numbering "Group I" (consonant-stem, more common) and "Group II" (vowel-stem, less common). Sometimes categorization is expanded to include "Group III" (special cases) for the irregular verbs する suru and 来る kuru; note however that there are other Japanese irregular verbs, though they are generally only slightly irregular.
Consonant-stem verbs end in -u (-au, -iu, -uu, -ou), -ku, -gu, -su, -tsu, -nu, -bu, -mu or -ru, but not -eu, -zu, -dzu, -fu, -pu, or the defective columns -yu or -wu.
All vowel-stem verbs end in either -iru or -eru. However, not all verbs ending in -iru or -eru are vowel-stem verbs; for example, hashiru, "run", is a consonant-stem verb. Verbs ending in -aru, -uru and -oru also exist, and are all consonant-stem.
The Japanese names ("5-class" and "1-class") are based on the number of vowel suffixes used to form verb roots for conjugations. Classical Japanese had more verb groups (such as 2-class and 4-class) which are archaic in Modern Japanese.
Consonant-stem verbs conjugate differently from the vowel-stem verbs. Consonant-stem verbs conjugate after a consonant, and vowel-stem verbs conjugate after a vowel, as can be seen in the following examples:
|Plain form|| yom.u ("read")
| hashir.u ("run")
| mi.ru ("see")
| tabe.ru ("eat")|
|Polite form|| yom.imasu
|Potential form|| yom.eru
|Volitional form|| yom.ou
- Note that colloquially the ら ra is dropped meaning these two become mireru and tabereru.
- Can also be written as mi.eru. The difference is like the difference between "can see" and "can be seen." Two consonant-stems that are also irregular are ik.eru/ik.areru ("can go") and kik.eru/kik.oeru ("can hear"). Other irregular verbs are suru->dekiru ("can do") and kuru->korareru ("can come").
Consonant-stem verbs ending in -u (-au, -iu and -ou) may not appear to conjugate "after a consonant"; for example, the polite form of kau (買う, "buy") is kaimasu (ka.u → ka.imasu). However, the stem is in these cases technically considered to end in the consonant w. The w is normally suppressed, but surfaces in the negative form, as in kaw.anai ("does not buy"). Traditionally these verbs ended in -hu, which is still seen on occasion in historical kana usage, and thus unambiguously ended in h.
The terms "consonant-stem" and "vowel-stem" come from considering the invariant part of the verb (the verb stem) on the basis of phonemes – concretely, by writing in rōmaji. This is an abstract perspective, as the consonant stem itself never occurs independently, but only with a following vowel, as Japanese words are formed of morae – concretely, writing in kana. For example, while the stem of yomu is yom-, the bare *yom is not an independent word.
The standard Japanese terms, ichidan and godan, literally "one row" and "five rows", more formally monograde and pentagrade, correspond to the number of different morae (kana) that appear in the stem forms of the verb, which are then optionally combined with a suffix to form a conjugated word. Formally, verbs are classified by which column of the gojūon their stem ends in, with vowel stem verbs further distinguished into i and e type. For example, 読む yomu is of マ行五段活用 ma-gyō go-dan katsuyō "ma-column five-row conjugation" type, as its stem form end in each of the five rows of the ま column, namely まみむめも:
- 読ま よま yoma- as in yomanai (negative, irrealis),
- 読み よみ yomi- as in yomimasu (polite non-past),
- 読む よむ yomu- as in yomu (plain non-past; dictionary form),
- 読め よめ yome- as in yomeba (conditional),
- 読も よも yomo- as in yomō (yomou) (hortative/volitional).
Note that the volitional o stem is historically the negative a stem with euphonic sound change – and the o stem is only used for the volitional form – so these verbs were traditionally called 四段 yodan "four-row, tetragrade", omitting the o form.
While the above uses are the most common uses of the respective stems, they are used in various other ways, particularly the i stem – for example 読み物 yomi-mono "reading material"; compare 食べ物 tabe-mono "food" for vowel stem.
By contrast, vowel stem verbs have a single stem form, ending either in i or e, accordingly as -iru or -eru. These are referred to respectively as 上一段 kami ichi-dan "upper one-row" and 下一段 shimo ichi-dan "lower one-row", due to i being above e in the aiueo vowel ordering. In full terminology, the column of the final kana is also listed. For 見る みる miru is of マ行上一段活用 ma-gyō kami ichidan katsuyō "ma-column upper one-row conjugation" type and has stem:
- 見 み mi-
while 食べる たべる taberu is of バ行下一段活用 ba-gyō shimo ichidan katsuyō "ba-column lower one-row conjugation" and has stem:
- 食べ たべ tabe-
In Japanese dictionaries, in the readings of conjugable words the stem and the inflectional suffix are separated by a dot (・), as in 赤い あか・い aka.i "red". This is used to distinguish verb type, with consonant stem verbs having only the last kana treated as suffix, while in vowel stem verbs the last two kana are treated as suffix. The column 行 of the conjugation form corresponds to the kana immediately after the dot. For example:
- 帰る かえ・る kae.ru "return" – consonant stem ラ行五段
- 変える か・える ka.eru "change" – vowel stem ア行下一段
Note that for one-row verbs with only two kana, the entire verb is treated as a suffix, and no dot is displayed, as it would appear before the word. For example:
- 要る い・る i.ru "need" – consonant stem ラ行五段
- 居る いる iru "be (animate)" – vowel stem ア行上一段
The terms "Group I", "Group II", and "Group III" are primarily used in Japanese language education, and may be notated as (I), (II), (III) next to a verb. Similarly, the terms "u verb" (う verb) and "ru verb" (る verb) are educational terms, and may be notated as （う） or （る）.
Verbs ending in -iru and -eru
Vowel-stem verbs, such as ⾒る miru "to see" and 食べる taberu "to eat," end either in -iru or -eru (there are no other basic-form endings for this group), so most verbs ending in -iru and -eru are vowel stem verbs, but some consonant-stem verbs have these endings, too (e.g. 散る chiru "to scatter," 抓める tsumeru "to pinch"), and there are also "homophone verbs" that have either a vowel stem or a consonant stem (e.g. ikiru vowel 生きる "to live, to stay alive," consonant 熱る "to become sultry"; shimeru vowel 閉める "to close [something]," consonant 湿る "to be damp").
A rule of thumb: If the vowel i/e of the ending -iru/-eru is part of a kanji (as in 契る chigi-ru "to pledge" and 嘲る azake-ru "to ridicule"), chances are high that the verb has a consonant stem. However, this rule is not valid for two-syllable verbs (⾒る mi-ru, for example, has a vowel stem) and verbs written only in hiragana (for example, びびる bibiru "to be surprised" and のめる nomeru "to fall forward" have consonant stems). Some consonant-stem verbs also have the syllable with the ending vowel written in hiragana, e.g. 混じる ma-jiru "to mingle" and the mentioned-above verb 抓める tsu-meru.
Examples of conjugation
The two "homophone verbs" ikiru and shimeru:
|Vowel stem (-iru)||Consonant stem (-iru)||Vowel stem (-eru)||Consonant stem (-eru)|
|Plain form|| iki.ru
|| shimer.u |
|Polite form|| iki.masu
|| shimer.imasu |
|Potential form|| iki.rareru
|Volitional form|| iki.you
List of consonant-stem verbs ending in -iru
|aburagiru||脂ぎる||to be greasy|
|bibiru||びびる||to be surprised|
|dojiru||どじる||to mess up|
|hiru||放る||to fart, to expel (from the body)|
|hojiru||穿る||to pick, dig out|
|hotobashiru||迸る||to gush, spurt|
|ibiru||いびる||to torment, roast|
|ijiru||弄る||to fiddle with|
|ikiru||熱る||to become sultry (note that ikiru (生きる) meaning "to live, to stay alive" is a vowel-stem verb)|
|iru||炒る||to boil down, to roast (note that iru (居る) meaning "to be" is a vowel-stem verb)|
|iru||入る||to go in (see iru above)|
|iru||要る||to need (see iru above)|
|kiru||霧る||to become misty (note that kiru (着る) meaning "to put on [clothing]" is a vowel-stem verb)|
|kiru||切る||to cut (see kiru above)|
|kishiru||きしる||to become misty|
|kishiru||軋る||to squeak, creak|
|kojiru||抉る||to gouge, wrench|
|kubiru||括る||to grip, strangle|
|kujiru||抉る||to gouge, scoop|
|mairu||参る||to come/go - humble|
|meiru||滅入る||to feel depressed|
|mikubiru||見縊る||to belittle; to despise|
|mojiru||捩る||to parody, to twist|
|mushiru||毟る||to pluck, to pick, to tear|
|nijiru||躙る||to edge forward|
|nonoshiru||罵る||to abuse verbally|
|ochiiru||陥る||to fall, sink|
|omoiiru||思い入る||to ponder, to contemplate|
|omoikiru||思い切る||to dare to (usually in the form omoikitte (思い切って) or omoikitta (思い切った).)|
|sebiru||せびる||to pester for|
|tagiru||滾る||to boil, to seethe|
|tamagiru||魂消る||to be frightened|
|tochiru||とちる||to muff lines|
|yajiru||弥次る・野次る||to jeer at|
|yogiru||過る||to pass by, to drop in|
|yojiru||捩る||to twist, distort|
List of consonant-stem verbs ending in -eru
|eru||彫る||to carve (note that eru (得る) meaning "to get, to obtain" is a vowel-stem verb)|
|eru||選る||to choose (see eru above)|
|eru||啁る||to ridicule (see eru above)|
|fukeru||耽る||to be absorbed in|
|fuseru||臥せる||to hide, lie in ambush|
|haberu||侍る||to attend on|
|hirugaeru||翻る||to turn over, to wave|
|hoteru||火照る||to flush, to feel hot|
|kaeru||反る・返る||to turn over (note that kaeru (変える) meaning "to alter" and kaeru (替える) meaning "to exchange" are vowel-stem verbs)|
|kaeru||返る・帰る・還る||to return (see kaeru above)|
|kaeru||孵る||to be hatched (see kaeru above)|
|kageru||陰る||to become dark, to be in shadow or shade|
|kakeru||駆ける||to run, to canter or gallop|
|kuneru||くねる||to be crooked|
|kutsugaeru||覆る||to be overturned|
|neru||練る||to temper, to refine, to knead (note that neru (寝る) meaning "to sleep" is a vowel-stem verb)|
|nomeru||のめる||to fall forward|
|numeru||滑る||to be slippery|
|seseru||挵る||to pick, play with|
|shaberu||喋る||to talk, to chat|
|shigeru||茂る||to grow thick|
|shikeru||湿気る||to become damp|
|soberu||そべる||to lie sprawled|
|takeru||猛る||to act violently|
|yomigaeru||蘇る||to be brought back to life, to be refreshed|
List of "homophone verbs" ending in -iru that have both a vowel stem and a consonant stem
|Verb||Vowel Stem||Consonant Stem|
|ikiru||生きる to live, to stay alive||熱る to become sultry|
|iru||居る to be||炒る to boil down, to roast 入る to go in 要る to need|
|kiru||着る to put on clothing||霧る to become misty 切る to cut|
List of "homophone verbs" ending in -eru that have both a vowel stem and a consonant stem
|Verb||Vowel Stem||Consonant Stem|
|eru||得る to get, to obtain||彫る to carve 選る to choose 啁る to ridicule|
|heru||経る to pass (time/through)||減る to decrease|
|kaeru||変える to alter 替える to exchange||返る ・ 帰る ・ 還る to return 孵る to be hatched|
|neru||寝る to sleep||練る to temper, to refine, to knead|
|shimeru||閉める to close (something)||湿る to be damp|
- sci.lang.japan FAQ's list of iru and eru consonant-stem verbs.
- Aeron Buchanan's Japanese Verb Chart, a concise summary of all Japanese verbs conjugations on one sheet of A4
- Seiichi Makino and Michio Tsutsui, A dictionary of intermediate Japanese grammar, published by The Japan Times, ISBN 4-7890-0775-8.