In Japanese, expressing uncertainty or conjecture is common in daily conversation. Mastering these expressions will make your Japanese sound more natural and nuanced. Two important patterns are ～でしょう (deshou) and ～かもしれません (kamoshiremasen). While both indicate uncertainty, they differ in the degree of certainty.
～でしょう (deshou) expresses a conjecture based on some evidence or reasoning. It conveys a higher degree of certainty than ～かもしれません. You can also use it to seek confirmation. Think of it as "I think..." or "Probably..." or even a rhetorical question.
Form:
*Important Note Regarding な-adjectives and Nouns: When attaching でしょう to a な-adjective or a noun, you usually don't need to add the "だ" (da) before でしょう in polite speech.
Examples:
| Japanese | Romaji | English Translation | Notes |
|---|---|---|---|
| 明日は雨が降るでしょう。 | Ashita wa ame ga furu deshou. | It will probably rain tomorrow. | Based on the weather forecast, perhaps? |
| 彼は学生でしょう。 | Kare wa gakusei deshou. | He is probably a student. | I saw him wearing a school uniform, maybe? |
| このケーキはおいしいでしょう。 | Kono keeki wa oishii deshou. | This cake is probably delicious. | It looks delicious, so I'm guessing. |
| あの人は田中さんでしょう。 | Ano hito wa Tanaka-san deshou. | That person is probably Mr./Ms. Tanaka. | Based on recognition, prior knowledge, etc. |
| 静かでしょう。 | Shizuka deshou. | It's probably quiet. | Speaking about a library or a similar place. The context implies the place that the subject is referring to. |
| もうすぐ着くでしょう。 | Mou sugu tsuku deshou. | We will probably arrive soon. | The speaker anticipates arriving soon, based on the current location and the expected travel time. |
Nuance and Usage of でしょう as a Question:
As mentioned earlier, raising the intonation at the end of a sentence ending with でしょう transforms it into a question, seeking confirmation or agreement. It's similar to adding "isn't it?" or "right?" in English.
| Japanese | Romaji | English Translation |
|---|---|---|
| 今日は暑いでしょう？ | Kyou wa atsui deshou? | It's hot today, isn't it? |
| これはあなたの本でしょう？ | Kore wa anata no hon deshou? | This is your book, right? |
| 彼はもう帰ったでしょう？ | Kare wa mou kaetta deshou? | He's already gone home, I guess? |
～かもしれません (kamoshiremasen) expresses a weaker possibility or uncertainty. It indicates that something could happen or might be true, but you're not very confident. It implies a lower probability than ～でしょう.
Form:
Examples:
| Japanese | Romaji | English Translation | Notes |
|---|---|---|---|
| 彼は来ないかもしれません。 | Kare wa konai kamoshiremasen. | He might not come. | I'm not sure if he will come or not. |
| 明日は寒いかもしれません。 | Ashita wa samui kamoshiremasen. | It might be cold tomorrow. | The weather is uncertain. |
| これは高いかもしれません。 | Kore wa takai kamoshiremasen. | This might be expensive. | Based on the appearance or brand, but I'm not sure of the exact price. |
| 彼女は病気かもしれません。 | Kanojo wa byouki kamoshiremasen. | She might be sick. | She looks pale, and hasn't been herself recently. |
| 電車が遅れるかもしれません。 | Densha ga okureru kamoshiremasen. | The train might be delayed. | Due to an accident or congestion, perhaps. |
| パスワードが間違っているかもしれません。 | Pasuwaado ga machigatteiru kamoshiremasen. | The password might be incorrect. | Trying to log into an account. |
| Expression | Usage Example (JP) | Romaji | English Translation | Degree of Certainty |
|---|---|---|---|---|
| ～でしょう | 彼は忙しいでしょう。 | Kare wa isogashii deshou. | He is probably busy. | Higher |
| ～かもしれません | 彼は忙しいかもしれません。 | Kare wa isogashii kamoshiremasen. | He might be busy. | Lower |
| ～でしょう | 明日は晴れるでしょう。 | Ashita wa hareru deshou. | It will probably be sunny tomorrow. | Higher |
| ～かもしれません | 明日は晴れるかもしれません。 | Ashita wa hareru kamoshiremasen. | It might be sunny tomorrow. | Lower |
Further Clarification through Scenarios:
Imagine you're waiting for a friend:
Scenario 1: Your friend is usually on time, and they said they were leaving work early. You would say: 「彼はもうすぐ来るでしょう。」 (Kare wa mou sugu kuru deshou.) - "He will probably arrive soon."
Scenario 2: Your friend is often late, and you haven't heard from them. You would say: 「彼は遅れるかもしれません。」(Kare wa okureru kamoshiremasen.) - "He might be late."
While ～でしょう and ～かもしれません are fundamental, here are a few more ways to express conjecture, expanding your vocabulary and nuance.
～はずです (hazu desu): "Should be," "Is supposed to." This implies a higher degree of certainty than でしょう, often based on expectations or rules.
～と思います (to omoimasu): "I think." This is a versatile phrase for expressing opinions and beliefs, but it can also express conjecture. It's more direct than でしょう or かもしれません, as it clearly states your own thought.
～んじゃない (janai)/～んじゃないですか (janai desu ka): "Isn't it?" "Don't you think?" Used to express conjecture while seeking agreement. Less formal than でしょう.
Politeness Levels: While both でしょう and かもしれません are polite, でしょう can sound more assertive depending on your intonation and the context. In very formal situations, consider using more polite alternatives, or softening your statements with phrases like 「～と思います」.
Overuse: Be mindful of overuse. Relying too heavily on these expressions can make you sound unsure or hesitant. Vary your language to express your thoughts with more confidence when appropriate.
Context is Key: The best choice between でしょう and かもしれません depends heavily on the context and the degree of uncertainty you want to convey. Pay attention to how native speakers use these expressions in different situations.
Translate the following into Japanese using でしょう or かもしれません (or, for an extra challenge, try using the alternative expressions like ～はずです or ～と思います):
彼女は家にいるかもしれません。(Kanojo wa ie ni iru kamoshiremasen.)
明日は晴れるでしょう。(Ashita wa hareru deshou.)
この本は面白いでしょう。(Kono hon wa omoshiroi deshou.)
彼は午後５時までに着くはずです。(Kare wa gogo goji made ni tsuku hazu desu.)
あのレストランはおいしいんじゃないですか。(Ano resutoran wa oishii janai desu ka?)
店は今日閉まっているかもしれません。(Mise wa kyou shimatteiru kamoshiremasen.)
Choose the appropriate expression (でしょう or かもしれません) for the following sentences, filling in the blank.
A: 今日は人が多いですね (Kyou wa hito ga ooi desu ne - There are a lot of people today, aren't there?)
B: ええ、今日は週末ですから、多い（ ）。 (Ee, kyou wa shuumatsu desu kara, ooi ( ). - Yes, because it's the weekend, it's probably crowded.)
A: 彼は来ると思いますか。(Kare wa kuru to omoimasu ka - Do you think he will come?)
B: うーん、忙しいと言っていましたから、来ない（ ）。 (Uun, isogashii to itteimashita kara, konai ( ). - Hmm, he said he was busy, so he might not come.)
この問題は難しい（ ）から、先生に聞きましょう。(Kono mondai wa muzukashii ( ) kara, sensei ni kikimashou. - This problem is probably difficult, so let's ask the teacher.)
多いでしょう (Ooi deshou)
来ないかもしれません (Konai kamoshiremasen)
難しいでしょう (Muzukashii deshou)