Presumptive

Production Rules:

	Rule	Meaning
Plain Affirmative	[う-stem] & だろう [u-stem] & darou	X probably [does], X probably will [do]
Polite Affirmative	[う-stem] & でしょう [u-stem] & deshou	X probably [does], X probably will [do]
Plain Negative	[あ-stem] + ない & だろう [a-stem] + nai & darou	X probably doesn't [do], X probably won't [do]
Polite Negative	[あ-stem] + ない & でしょう [a-stem] + nai & deshou	X probably doesn't [do], X probably won't [do]

Note that the presumptive is formed by simply adding だろう (darou) for the plain case or でしょう (deshou) for the polite case to the plain forms of the nonpast indicative.

Inflection Examples:

	Plain Affirmative	Polite Affirmative	Plain Negative	Polite Negative
食べる taberu (to eat)	食べるだろう taberu darou	食べるでしょう taberu deshou	食べないだろう tabenai darou	食べないでしょう tabenai deshou
話す hanasu (to speak)	話すだろう hanasu darou	話すでしょう hanasu deshou	話さないだろう hanasanai darou	話さないでしょう hanasanai deshou
歩く aruku (to walk)	歩くだろう aruku darou	歩くでしょう aruku deshou	歩かないだろう arukanai darou	歩かないでしょう arukanai deshou
泳ぐ oyogu (to swim)	泳ぐだろう oyogu darou	泳ぐでしょう oyogu deshou	泳がないだろう oyoganai darou	泳がないでしょう oyoganai deshou
呼ぶ yobu (to call)	呼ぶだろう yobu darou	呼ぶでしょう yobu deshou	呼ばないだろう yobanai darou	呼ばないでしょう yobanai deshou
飲む nomu (to drink)	飲むだろう nomu darou	飲むでしょう nomu deshou	飲まないだろう nomanai darou	飲まないでしょう nomanai deshou
死ぬ shinu (to die)	死ぬだろう shinu darou	死ぬでしょう shinu deshou	死なないだろう shinanai darou	死なないでしょう shinanai deshou
作る tsukuru (to make)	作るだろう tsukuru darou	作るでしょう tsukuru deshou	作らないだろう tsukuranai darou	作らないでしょう tsukuranai deshou
待つ matsu (to wait)	待つだろう matsu darou	待つでしょう matsu deshou	待たないだろう matanai darou	待たないでしょう matanai deshou
洗う arau (to wash)	洗うだろう arau darou	洗うでしょう arau deshou	洗わないだろう arawanai darou	洗わないでしょう arawanai deshou

Irregulars:

	Plain Affirmative	Polite Affirmative	Plain Negative	Polite Negative
する suru (to do)	するだろう suru darou	するでしょう suru deshou	しないだろう shinai darou	っしないでしょう shinai deshou
来る kuru (to come)	くるだろう kuru darou	くるでしょう kuru deshou	こないだろう konai darou	こないでしょう konai deshou

Usage Notes & Examples:

This form is used to express some doubt or conjecture on the part of the speaker, similar to interjecting "probably" in English. Without combining it with another form like the progressive, the meaning is similar to the nonpast indicative, expressing a conjecture about a state, or habitual or future action. In Japanese one doesn't speak of someone else's presumptive actions (desires, etc.) with any certainty, so among other ways, this form can be used to add the necessary uncertainty.
- 経済状況はすぐによくなるだろう。
  keizai joukyou ha sugu ni yoku naru darou.
  Economic conditions will probably get better soon.
- 田中さんは随分忙しいそうで、今夜来ないだろう。
  tanaka-san wa zuibun isogashii sou de, kon'ya konai darou.
  I heard that Mr. Tanaka is extremely busy, so he probably won't come tonight.
- ここから東京まで飛行機で13時間ぐらいかかるでしょう。
  koko kara toukyou made hikouki de juusan jikan gurai kakaru deshou.
  From here to Tokyo by plane probably takes about 13 hours.
This form can also be used to solicit agreement or soften the tone of a statement.
The plain forms using だろう (darou) can sound somewhat abrupt or assertive, even when talking to equals. You may want to use the polite forms even in friendly contexts. It is acceptable to use the plain forms when talking to yourself, or to people you would otherwise be on informal terms with about impersonal third-party subjects. Of course, this is all a matter of degree. An all-male group of friends, or a superior speaking to an inferior would not be likely to use the polite forms.

Presumptive

Production Rules:

Inflection Examples:

Irregulars:

Usage Notes & Examples:

Expressions