ISORI

〜おう / 〜よう

Conjugation:

let's / I'll

The plain volitional: a casual "let's…", or "I'll…" when you decide something or think aloud.

Conjugation rules

  • For godan verbs, change the last う-sound to its お-sound, then add う: 行(い)く becomes 行(い)こう.
  • For ichidan verbs, replace る with よう.
  • する becomes しよう and 来(く)る becomes 来(こ)よう (irregular).

Examples

godan
行(い)く(to go)行(い)こう
ichidan
食(た)べる(to eat)食(た)べよう
irregular
する(to do)しよう
来(く)る(to come)来(こ)よう

Less common

愛(あい)する(to love)愛(あい)そう

Some する verbs with a one-kanji stem, like 愛(あい)する, take the godan ending, as if the verb were 愛(あい)す.

Example sentences

映画(えいが)を見(み)よう。

Let's watch a movie.

明日(あした)は早(はや)く起(お)きよう。

I'll get up early tomorrow.

Notes

  • The polite version is 〜ましょう: 行(い)きましょう.
  • Adding か makes an offer or a suggestion: 手伝(てつだ)おうか (shall I help?).
  • With と思(おも)う it says what you are thinking of doing (〜ようと思(おも)う); with とする it means "try to" or "be about to" (〜ようとする).

Common mistakes

  • Using the plain volitional with someone you should be polite to. Use ましょう instead.