Japanese verbs do not have singular/plural and don’t change the conjugation depending on the person they refer to.
They are divided into 3 main groups: godan verbs, ichidan verbs and ‘suru’/’kuru’ verbs (irregular).
The most common ones are the ‘godan verbs’.
In this group the positive base (dictionary form) ends in u, ku, gu, su, tsu, nu, bu, mu, ru.
There are 5 main bases for each verb:
1. The negative base, used for the colloquial negative form
2. the indefinite base, used to form the formal, positive sentences with the following endings:
+masu (present)/mashita (past)/tai desu (want to+verb)
3. the positive base, used for the colloquial form of present and future
4. the conditional/imperative base, used for the imperative or with the ending ru for the potential form (ability), or the ending ba for the conditional form
5. this is not a real base, but is used to form the volitive of the verb
The ‘godan verbs’ change their ending depending on the base used:
Kaku (to write)
kaka negative
kaki indefinite (by adding masu you form the present)
kaku positive / colloquial (dictionary form)
kake conditional / imperative
kakō volitive
Examples:
Kare wa tegami o kakanai. (kaka+nai) – He doesn’t write a letter
Kare wa tegami o kakimasu. (kai+masu) – He writes a letter (formal)
Kare wa tegami o kaku – He writes a letter– (colloquial form)
Kare wa tegami o kakeru – He can write a letter
Tegami o kakō – Let’s write a letter
Kau (to buy)
Ka+wa negative
Ka+i indefinite
Ka+u positive / colloquial
Ka+e condizionale / imperative
Ka+ō volitive
Examples:
Karera wa hon o kawanai (kawa+nai) – They don’t buy the book
Karera wa hon o kaimasu (kai+masu) – They buy a book
Karewa wa hon o kau (kau) – They buy a book
Karera wa hon o kaeru (kae+ru) – They can buy a book
Hon o kaō – Let’s buy a book
Tsukuru (to build)
Tusuku+ra negative
Tsuku+ri indefinite
Tsuku+ru positive / colloquial
Tsuku+re conditional / imperative
Tsuku+rō volitive
Examples:
Kare wa tatemono o tsukura nai (tsukura+nai) – He doesn’t build a building
Kare wa tatemono o tsukurimasu.(tsukuri+masu) – He builds a building
Kare wa tatemono o tsukuru.(tsukuru) – He builds a building
Kare wa tatemono o tsukureru.(tsukure+ru) – He can build a building
Tatemono o tsukurō – Let’s build a building
Hanasu (to speak)
Hana+sa negative
Hana+shi indefinite
Hana+su positive / colloquial
Hana+se conditional / imperative
Hana+sō volitive
Examples:
Watashi wa nihongo o hanasanai – I don’t speak Japanese
Watashi wa nihongo o hanashimasu – I speak Japanese
Watashi wa nihongo o hanasu – I speak Japanese
Watashi wa nihongo o hanasemasu – I can speak japanese
Nihongo o hanasō – Let’s speak Japanese
Other ‘godan’ verbs are:
Yomu (to read), Iku (to go), Toru (to take), Iu (to say), Asobu (to play), Nomu (to drink), Oyogu (to swim), Matsu (to wait), ecc…
