Japanese conjugation
); the conjugated forms can express meanings such as negation, present and past tense, volition, passive voice, causation, imperative and conditional mood, and ability.
For example, 知る (shiru) and 着る (kiru) belong to different verb categories (godan and ichidan, respectively) and therefore follow different conjugation patterns.
Ichidan verbs are simpler to conjugate: the final kana, which is always る (ru), is simply removed or replaced with the appropriate inflectional suffix.
This phenomenon can be observed by comparing conjugations of the two verb types, within the context of the gojūon table.
[3] However, as a result of the language evolving,[4][5] historical sound shifts,[6][7] and the post‑WWII spelling reforms,[8] three additional sub‑bases have emerged for verbs (seen in the table below as the Potential, Tentative, and Euphonic bases).
Meanwhile, verbs no longer differentiate between the terminal form (終止形, shūshikei, used to terminate a predicate) and the attributive form (連体形, rentaikei, used to modify a noun or noun phrase) bases (these bases are only distinguished for na‑adjectives in the modern language, see Japanese adjectives).
With ichidan verbs, the base is derived by removing or replacing the final る (ru) kana.
This evolved into the modern passive ending （ら）れる (-(ra)reru), which can similarly express potential and spontaneous senses.
[4] The historical development of the kanōkei base is disputed, however the consensus is that it stemmed from a shift wherein transitive verbs developed an intransitive sense similar to the spontaneous, passive, and potential, and these intransitive forms conjugated in the 下二段活用 (shimo nidan katsuyō, lower bigrade conjugation pattern) of the Classical Japanese of the time.
The negative form is compatible with the ～で (-de) particle for additional functions, such as requesting someone to cease/desist or joining a subordinate clause.
The negative continuous form is created by using the mizenkei base, followed by the 〜ず (zu) suffix; equivalent to replacing 〜ない (-nai) with 〜ず (-zu) in the table above.
The verb has the "negative continuous tense" unless followed by the に (ni) particle, where its meaning changes to "without".
Similar to the word "and" in English, the te form connects clauses to make longer sentences.
(See also: Euphonic changes) The te form is compatible with particles for additional functions, such as giving permission or expressing prohibition.
Finally, the te form is necessary for making polite requests with 下さる (kudasaru) and くれる (kureru).
[44][42] During speech, the speaker may terminate a sentence in the te form but slightly lengthen the vowel sound as a natural pause: てぇ (te…).
The conjunctive form is compatible with particles for additional functions, such as expressing purpose[49] or a firm avoidance.
When a pair of verbs are not directly related but happen during a shared period of time, only the conjunctive form can bridge them.
In practice however, such a strategy is more readily accustomed to writing and more difficult to control in spoken conversation (where the te form is usually elected for every verb).
The volitional form is also used to describe intention 〜と思う (-to omou)[57] an attempt 〜とする (-to suru) or an imminent action 〜としている (-to shite iru).
The passive form (受身形, ukemikei) refocuses the verb as the target objective of a sentence; it emphasizes the action as the detail of importance.
This makes it impossible to distinguish whether an ichidan verb adopts a passive or potential function without contextual information.
For instance, a passive verb (e.g. 言われる (iwareru, be said)) can conjugate using the ichidan pattern for the te form (て形, te kei) to join sequential statements (言われて (iwarete)), or the conjunctive form to append the polite -masu (〜ます) auxiliary verb (言われます (iwaremasu)).
For instance, a causative verb (e.g. 言わせる (iwaseru, caused to say)) can conjugate using the ichidan pattern for the te form (て形, te kei) to join sequential statements (言わせて (iwasete)), or the conjunctive form to append the polite -masu (〜ます) auxiliary verb (言わせます (iwasemasu)).
However, because words such as 待たせられる (mataserareru) are considered difficult to pronounce, the conjugational suffix is often contracted in colloquial speech.
However, unlike in English, the potential form does not request permission; the phrase この林檎が食べられる？ (kono ringo ga taberareru?, "Can I eat this apple?"
The potential form is created by using the kanōkei base, followed by the る・(ら)れる (ru/(ra)reru) suffix.
This makes it impossible to distinguish whether an ichidan verb adopts a passive or potential function without contextual information.
However, in colloquial speech the ら (ra) is removed from られる (rareru) in a phenomenon known as ら抜き言葉 (ranuki kotoba).
For instance, a potential verb (e.g. 言える (ieru, can say)) can conjugate using the ichidan pattern for the te form (て形, te kei) to join sequential statements (言えて (iete)), or the conjunctive form to append the polite -masu (〜ます) auxiliary verb (言えます (iemasu)).
