The Auxiliaries だろう・でしょう
In this lesson, we will go into depth on the auxiliaries だろう・でしょう, which are the plain speech and polite speech equivalents of each other for denoting “supposition,” both neatly translating as “probably.” Both are combinations of the auxiliary verb ～う attached to the 未然形 of the copulas だ・です.
In addition to creating the volitional form, the auxiliary verb ～う may also indicate supposition, which refers to a statement that is assumed to be true, often without definitive proof. While the auxiliary verb ～う also plays this role with other parts of speech, for now, we will just look at how it functions within だろう・でしょう.
To conclude, we will also learn about variants of these auxiliaries in other speech registers: ～でありましょう・～でございましょう・～でいらっしゃいましょう・～であろう.
だろう・でしょう
The auxiliaries だろう・でしょう both neatly translate as “probably” or the like, and in an interesting turn of events, they may both attach to all predicate types.
| Predicate Type | 接続 | Ex. |
| Verbal | 終止形 | する｛だろう・でしょう｝ will probably do |
| Adjectival | 終止形 | 新しい｛だろう・でしょう｝ is/will be probably new |
| Adjectival Noun | Root (語幹) | 簡単｛だろう・でしょう｝ is/will be probably easy |
| Nominal | Root (語幹) | 明日｛だろう・でしょう｝ will probably be tomorrow |
Interpretation as far as tense and aspect are concerned will be context-dependent, but it is worth noting that, as the chart below indicates, verbal predicates + ～だろう・でしょう are interpreted in the future tense, whereas nominal, adjectival, and adjectival noun predicates may be interpreted as either being present or future tense. “Would be…” is also often an appropriate translation across the board if the suppositional statement is purely hypothetical.
At the turn of the 20th century, だろう・でしょう replaced the original means of representing supposition with verbs and adjectival predicates1, which involved the auxiliary verb ～（よ）う directly attaching to their 未然形.
i. 明日は雨が降ろう。(Old-Fashioned)
ii. 明日は雨が降るだろう。(Modern)
While not grammatically incorrect, i. and sentences like it which utilize the traditional conjugating of ～（よ）う with verbs or adjectives is no longer commonplace in both the spoken and written languages2. As such, the examples that follow below all follow the pattern established in ii.
1. 食べないほうがいいだろう。
It’s probably best not to eat (it).
2. もうすぐ（雨が）止むだろう。
It will likely stop raining soon.
3. 出席者は高々10人だろう。
There will likely be no more than ten attendees.
4. 今晩は雪でしょう。
It’ll probably snow this evening.
5. 薬で頭痛は収まるでしょう。
Your headache should subside with medicine.
6. 戦争は終わるだろう。
The war will likely end.
7. 諒君はもうすぐ帰ってくるだろう。
Ryo-kun will probably be home soon.
8. サンドイッチに入れても美味しいでしょう。
It would also probably taste good in a sandwich.
9. 諦める事は簡単でしょう。
Giving up would be easy enough.
10. 狙い通りだろう。
That’s what (you/we) were aiming for.
Translation Note: At times, it is not always necessary to include “probably/likely” in the English translation if the resultant phrasing in English itself can be just as easily perceived as a suppositional statement.
11. 台風で避難警告が出ているが自分だけは大丈夫だろう。
There’s an evacuation warning for the typhoon, but surely I’ll at least be fine.
12. 色々世間を騒がせているが、うちの会社は問題ないだろう。
There’s been a lot of uproar in the world, but I’m sure our company won’t be affected.
It may go without saying that ～だろう・でしょう may also directly follow the plain forms of the past, negative, and negative-past forms of all predicate types.
13. さっき言ったでしょう。
I told you so.
14. 常識のある人ならそんな言い方はまずしないでしょう。
People with common sense would never phrase things like that in the first place.
16. 辛かっただろう。泣きたかっただろう。
I’m sure it was tough. I’m sure you wanted to cry.
17. IMABIの内容は５年前の自分には理解できなかっただろう。
I probably wouldn’t have been able to understand IMABI’s content five years ago.
18. 食べていたら、お腹が空いていなかったでしょう。
If I had been eating, I wouldn’t have been hungry.
～だろう・でしょう ＋ ～が・けれど
As modal auxiliaries marking supposition, だろう・でしょう may both combine with the conjunctive particles が and けれど (along with all of its forms).
19. 一回の選挙で現状は劇的には変わらないだろうけど、風景はどんなになるだろうか？
One election is unlikely to dramatically change the status quo, but what will the landscape look like?
20. 人によるでしょうけど食事を楽しむ環境ではありません。
I’m sure it depends on the person, but this is not the kind of environment for enjoying a meal.
21. オレのせいにすることないだろうが、どうせ出かけるつもりだったんじゃないか。
There’s surely no way you’d blame it on me, but were you not planning on heading out anyway?
The conjunctive particles が and けれど (along with all of its forms) may also function as final particles. ～だろうが is heavily used by male speakers when stressing a point. If female speakers are to similarly stress a point, they often deviate to the more polite ～でしょうけ（れ）ど, which may be used by men as well for the same polite effect. ～でしょうが is also possible, but when used by a male speaker, the tone is just as stern and scary as if the speaker had just stuck to ～だろうが.
22. どうです、大したものでしょうが。
Well? I’m sure it’s quite a big deal, but (I digress).
～だろう・でしょう w/ Final particles
～だろう is frequently followed by final particles such as よ, ね, and な. As for ～でしょう’s relation with these same final particles, the situation is far more complicated. With ～でしょう being polite, the affirmative tone is lessened. As an effect of this tone leveling, ね is the most appropriate of the three particles for it. In fact, ～でしょうよ can come off “oh, how come you don’t know that?” which is not the nicest thing in the world to say. Meanwhile, ～でしょうな is stilted toward older male speech but heavily underused in comparison to ～だろうな.
23. よく知らない人に使うと慎みのない下品な言い方であることが分かるでしょうよ。
If you use (that) with someone you don’t know well, you’d surely realize just how immodest and vulgar the pattern is.
24. 不便だろうな。
That’s probably inconvenient.
25. 私だったらそんな馬鹿げたことしなかったでしょうね。
If it were me, I wouldn’t have done something so stupid.
だろう・でしょう？
With a ⤴ intonation, だろう・でしょう, create rhetorical questions equivalent to “right…?” depending on the predicate type and conjugation used.
26. 嘘だろう？
You got to be kidding, right?
27. さっき言ったでしょう？
I told you that earlier, right?
With a tapering intonation (↘) , だろう・でしょう create rhetorical questions spoken to oneself, with no intended audience (or a listener expected to respond). The presence of ？ or the lack thereof is not a litmus test for determining the nature of a rhetorical question so much as the presence of an interrogative.
28. 私は誰だろう。
Who am I?
29. 相手が本当に知りたいことは何だろう？
What could the other person really want to know?
30. 君に出逢ったのはいつだろう？
When was it that I met you?
だろうか
～だろうか may be used to express personal doubt, especially in one’s inner monologue. This is the case for both men and women, and in this sense, it can be translated as “I wonder…”
31. 何時だろうか。
I wonder what time it is.
32. いつ行うだろうか。
I wonder when (he)’ll carry it out.
When spoken and not a part of one’s inner monologue, ～だろうか is paired with a rising intonation to direct serious doubt at someone about something or that individual. Such utilization is more typical of male speech.
33. あんな馬鹿な行為が許されるだろうか。
How would such a stupid action be allowed?
でしょうか
With a standard question intonation (higher but not rising), ～でしょうか is most utilized as a more formal replacement of ～ですか, but unlike ～ですか, it may be paired with all predicate types and all basic forms (non-past, past, negative, negative-past).
With nominal, adjectival, and adjectival noun predicates, it may be viewed as being entirely synonymous as ～ですか.
34. こちらでお間違いないでしょうか。
Are you sure this is correct?
35. 本日はどういったご用件でしょうか。
What can (I/we) help you with today?
36. 資料に不備はございませんでしょうか。
Is there anything missing/insufficient in the documents?
A common feature of バイト敬語 is the phrase よろしかったでしょうか, which is seen as an uber-formal means of saying ｛良い・よろしい｝でしょうか. This is viewed as being ungrammatical by many, not for being too formal, but for how ～た ought to function to verify something with the listener but predicated on an established situation. When verifying something that is clearly in the moment, relating the question to some past conversation would be awkward at best.
37a. 何時ごろがよろしいでしょうか。
37b. 何時ごろがよろしかったでしょうか。△
About what time would be great?
You may also see ～でしょうか used to create formal requests, the heightened formality providing a cushioning effect.
38. 恐れ入りますが、お見積りを明日までに頂くことは可能でしょうか。
If it’s not too much to ask, would it be possible to receive the quote by tomorrow?
Meanwhile, with verbal predicates, it may be viewed as a politer rendition of ～ますか, with the degree of doubt or sense of confirmation involved dependent on context, capable of showing up in all sorts of scenarios in which the speaker is asking a listener for their opinion.
39. 明日は晴れるでしょうか。
Will it be clear weather tomorrow?
40. この問題は来週の試験に出るでしょうか。
Will this problem appear on next week’s exam?
41. 彼女からもう返事は来ないでしょうか。
Will I not get any replies from her anymore?
42. 明日以降に寒くなるようですが、雪は降るでしょうか？
It looks like it’s going to get colder from tomorrow onwards, but will it snow?
w/ ～のだ
The mood marker ～のだ adds a layer of modality to だろう・でしょう, tying the suppositional ending to a greater context.
By adding the layer of modality (supposition) provided by ～う into the picture, we get three viable combinations.
43. テイラー君が来ないなあ。きっと何かがあったんだろう。(Situation-Oriented, Q=Pv)
Taylor-kun hasn’t come, huh. Something surely must’ve happened.
44. 君は用事とかあるんだろう。(Interpersonal, Q=Pv)
I’m sure you got errands to do or something (from what I know).
45. そうか、ひっくり返して作るんだろう。(Situation-Oriented, Q=Pnv)
Oh, you probably make it by turning it upside down.
Using ～のだろう・のでしょう in a question adds yet another layer of modality.
- ～のだろうか may either be used in inner monologue or directed at a listener in a rhetorical question in the same manner as ～だろうか, but by relating the question to a greater context, the doubt expressed is higher with a feeling of more questions asked than answered. When directed at a listener, its stern tone makes it inappropriate in polite, formal settings.
- ～のでしょうか similarly expresses a high degree of doubt toward the validity of the statement within some greater context, but thanks to it being a form of です, the question remains polite and appropriate in formal settings. It is also possible and more than appropriate in non-rhetorical questions.
- Both ～でしょうか and ～のでしょうか are notably not used in inner monologue-type speech, as politeness is marked when speaking toward others, not at oneself.
As also indicated by the example sentences above, ～の is usually contracted to ～ん in the spoken language. Depending on the level of formality, this contraction may also be present in the written language.
46. 渋谷駅の工事っていつ終わるんだろうか。
Just when is the construction at Shibuya Station going to end?
47. 犯人なのではないだろうか。
Isn’t he supposed to be the criminal?
48. 誰が議事堂に行くのだろうか。
Who would go to the Diet?
49. 漢検１級に合格した人はどのくらいいるのでしょうか。
So, about how many people have passed the Kanken Level 1?
50. 何時に集まればいいのでしょうか。
What time should we assemble?
51. カタルーニャ語がペラペラになるまでに、どのぐらい勉強が必要なのでしょうか。
How much studying will it take to become fluent in Catalan?
52. 文章を書くときに、常用漢字表にない漢字を使ってはいけないのでしょうか。
When writing, should I not use kanji that are not on the Joyo Kanji List?
While rhetorical in nature, questions posed with the particle か in these environments do still solicit a continued discussion on the matter. When the particle か itself is ellipsed, the nature of the rhetorical question is quite different, instead soliciting the listener(s) to concur, which can also elicit various emotional responses depending on the tone of the speaker. For instance, the statement posed in Ex. 53 could very easily be interpreted as condescending.
53. こんな簡単な工夫を今まで思いつかなかったんだろう？
You hadn’t come up with such a simple idea as this so far, am I right?
～ますでしょうか
Rapidly gaining popularity, ～ますでしょうか is the latest trend in 敬語 that is here to say. In a prescriptive understanding of grammar, the pattern is ungrammatical due to being a case of 二重敬語3. Despite a fleeting minority that find this trendy ending inappropriate, any instance in which ～ます is used in a question is bound to have でしょうか follow in current language use4.
54 日本に来られて何年になりますでしょうか。
How many years has it been since you’ve come to Japan?
55. お分かりになりますでしょうか。
Do you understand?
56. お手数ですが毎週日本時間10時までにタスク表の更新と貼り付けをお願いできますでしょうか。
I apologize for the inconvenience, but could I please ask you to update and post the task list every week by 10:00 JST?
57. 谷川さんのご指摘の通り、ご訂正いただけますでしょうか。
Could you please make the correction just as Tanigawa-san has pointed out?
58. 今お時間ありますでしょうか？
Do you have time now?
だろうに・でしょうに
Before the rise of the conjunctive particle のに, its predecessor, the conjunctive particle に, could be used in the sense of “even though.” Often used to indicate sympathy and/or criticism at a situation, it carries on this meaning when following ～だろう・でしょう, capable of appearing in both sentence-medial and sentence-final positions.
59. 苦しかっただろうに、よく頑張った。
Even though it was supposed to be painful, he persevered well.
60. 人生をもう一度やりなおせたらどんなにいいだろうに。
How I wish I could live my life again!
61. もう少し早く出れば間に合っただろうに。
If we only left a little bit more early, we would have made it on time.
62. 喜ばしかったでしょうに、お旅は残念でした。
Even though one would have thought it to be delightful, the trip was regrettable.
63. 遠かったでしょうに、歩いてきたのですか。
Although one would think it to have been far, you came here by walking?
64. もっといいのがあっただろうに・・・
I’m sure you had something better (than this)…
～だろ・でしょ
In casual conversation, ～だろう・でしょう may be shortened to ～だろ・でしょ respectively. In the case of ～でしょ, be careful determining when casual polite speech is appropriate. For instance, female speakers may find ～でしょ easier to use in their everyday speech among friends, whereas both men and women would refrain from abbreviating either auxiliary in writing and/or non-casual contexts.
65. うまいだろ？
It’s good, right?
66. 「美味しいでしょ？」「うん！」
“It’s delicious, right?” “Sure is!”
～でありましょう
～でございましょう
～でいらっしゃいましょう
Incidentally, ～でしょう has its own honorific versions:
| 敬語 Type | |
| 丁重語 | ～でありましょう ～でございましょう |
| 尊敬語 | ～でいらっしゃいましょう |
| 謙譲語 | ～でございましょう |
Of these, ～でありましょう has been dramatically falling out of use in the last thirty years; however, in highly formal (often political) interactions, the other honorific forms ～でございましょう and ～でいらっしゃいましょう hold on, ironically likely due to being so longwinded.
67. あちらの方をご存じでありましょうか。
Do you know that individual?
68. 極めて良心的な店でありましょう。
My, is it not an extremely upright store.
69. この点、いかかでございましょう？
Regarding this point, what are your thoughts?
70. こうした信仰があちこちに広まったでございましょう。
This faith seems to have spread far and wide.
71. 大臣は報道ということについて、大変原則的なことですけれども、どのようにお考えでいらっしゃいましょうか。
Minister, while I know this is a very principled matter, what are you thoughts on the reporting?
であろう
The uncontracted form of the auxiliary ～だろう is ～であろう. This form is rather formal and preferred in statements that are meant to sound more objective. It may appear in all instances in which ～だろう may appear5.
72. 努力の甲斐があれば成功するであろう。
Success will surely reward you for availing efforts.
73. 必ずや成功するであろう。
You will absolutely succeed.
74. エジプトでは反政府派のデモ隊は逆境にあっても、挫けないであろう。
Even amid adversity, the anti-government demonstrators in Egypt will surely not crumble.
75. すると、ペテロが答えた、「悔い改めなさい。そして、あなたがたひとりびとりが罪のゆるしを得るために、イエ ス・キリストの名によって、バプテスマを受けなさい。そうすれば、あなたがたは聖霊の賜物を受けるであろう。 …」
Then, Peter said unto them, “Repent and be baptized everyone of you in the name of Jesus Christ for the remission of your sins, and you shall receive the gift of the Holy Ghost.
From 『使徒行伝 第2章38節 ＝ Acts 2:38』
- Given that だろう・でしょう are forms of the copula, their appearance after the 終止形 of non-nominal predicates is extraordinary yet also similar to the copula’s appearance in other environments, such as being a politeness marker via ～です after adjectival predicates or as ～でした following ～ません. In the context of だろう・でしょう, the “declarative” modality of its copular component is toned down via the auxiliary verb ～う, allowing for ～だろう・でしょう to both be viewed as a grammaticalized, single-word auxiliary for marking supposition. ↩︎
- The auxiliary verb ～う may still be used to mark supposition with verbal and adjectival predicates in Modern Japanese. However, this is largely only seen in literature, particularly in works from the early 1900s when the shift to using 終止形＋だろう・でしょう became prevalent. ↩︎
- 二重敬語 expressions are worthy of study in their own right. Despite existing for millennia, their continued prevalence has been frowned upon in the modern era, largely for being unnecessarily verbose and incongruent with rigid standards for language use imposed during the formation of the standardized variety of Japanese (標準語). The impetus for why speakers still choose to prefer 二重敬語 is to be as polite as possible, and in doing so, in their minds, being overly polite is necessary. ↩︎
- Moreover, the inclusion of the mood marker ～のだ to avoid “ungrammaticality” changes the nature of the question substantially, making it NOT a viable easy fix as is often touted. ↩︎
- While its presence after adjectival and verbal predicates is rather anachronistic, it is far more common than following the traditional means of attaching ～う to their respective 未然形. ↩︎