If you've been reading NDLs since we started doing JLPT lessons way back in October of last year, then today is a very happy day for you: This is our final N5 lesson!

Which means that it's time for me to get to work on compiling an awesome N5 lesson pack for NDL Premium subscribers.

In this final N5 lesson, we're looking at:

JLPT N5: でしょう・だろう (probably; most likely)

Now, if my grammar books are to be trusted, then だろう is actually N4 grammar, but でしょう shows up in N5 both when it is used to seek agreement (like we saw in this lesson: [NDL #392] - JLPT N5: でしょう (seeking agreement)) and when it is used for conjecture (i.e. the usage we're looking at in this lesson).

But we're covering both でしょう and だろう for a couple of reasons. (1) This lesson is our transition into N4, and (2) でしょう and だろう (as they are used in this lesson) mean the same thing, just でしょう is more polite than だろう.

OK. Let's get to work.

If you think that something is probably or mostly likely going to happen (or probably or most likely did happen), then you can put でしょう・だろう at the end of your sentence.

Here's an example:

あのカップルはそのうち別れるだろう。
あの　カップル　は　そのうち　わかれる　だろう。
They'll probably break up before long.
Literally: “that + couple + は + before very long + split up + だろう.”

The speaker in this case does not know for sure if the couple will break up. Rather, it is the speaker's guess / conjecture / prediction.

Compare this to the following more assured (and rude) example:

あのカップルはそのうち別れるよ。
あの　カップル　は　そのうち　わかれる　よ。
They'll break up before long.
Literally: “that + couple + は + before very long + split up + よ.”

This sounds stronger because it does not have the word だろう--the same way the English sounds stronger without the word "probably."

As mentioned above, in more polite sentences we can use でしょう instead of だろう：

週末は全国的に気温が下がるでしょう。
しゅうまつ　は　ぜんこくてき　に　きおん　が　さがる　でしょう。
The temperature will likely drop this weekend throughout the country.
Literally: “weekend + は + nationwide + に + (atmospheric) temperature + が + go down + でしょう.”

The "でしょう・だろう of conjecture" is very commonly used in weather forecasts, as we see here.

👷 Construction 👷

Putting together phrases with でしょう and だろう is relatively simple: Just put a word in plain form directly before either one.

For example, we have already seen:

(Plain Form) VERB + でしょう・だろう

別れるだろう
わかれる　だろう。
will probably break up
Literally: “split up + だろう”

下がるでしょう
さがる　でしょう
will likely drop
Literally: “go down + でしょう”

And we'll also see でしょう coming after だった later (which is technically a plain form copula [=だ or だった], but for simplicity, let's just call it a verb):

大変だったでしょう
たいへん　だった　でしょう
must have been difficult
Literally: “hard / tough + was (=だった) + でしょう”

In that sentence, we're using past tense, so we need だった, but when you just want to say "NOUN / Na-ADJECTIVE + でしょう・だろう" in the present or future tense, then you do NOT include だ：

NOUN / Na-ADJECTIVE + でしょう・だろう

男の子だろう
おとこのこ　だろう
probably a boy
Literally: “boy + だろう”

暇だろう
ひま　だろう
probably free
Literally: “spare time / free + だろう”

お腹の子はきっとまた男の子だろう。
おなか　の　こ　は　きっと　また　おとこのこ　だろう。
I’m sure it’s another boy.
Literally: “child one is expecting (=stomach + の + child) + は + surely + again + boy + だろう.”
Note: We can imagine that the speaker is a pregnant mother who has already had a baby boy before.

たくみなら暇だろう。電話して誘ってみよう。
たくみ　なら　ひま　だろう。　でんわ　して　さそって　みよう。
Takumi’s probably free. [Takumi’s always free.] Let’s call and invite him. [I think I'll call and invite him.]
Literally: “Takumi + if (it’s the case that) + bored / spare time / free + だろう. + phone + do (and) + invite (and) + let’s see.”

Note that we can also express conjectures about things that happened in the past (not just in the present/future) using でしょう and だろう：

ナイジェリア人の彼にとって、漢字の習得は大変だったでしょう。
ナイジェリアじん　の　かれ　にとって、　かんじ　の　しゅうとく　は　たいへん　だった　でしょう。
Being from Nigeria, learning kanji must have been difficult for him.
Literally: “Nigerian (person) + の + he + にとって (= for; regarding), + kanji + の + learning / acquisition + は + hard / tough + was (=だった) + でしょう.”
Note: The nuance here is that learning kanji would not be difficult for people from some Asian countries (e.g. China, Taiwan, etc.), but it would be difficult for people from countries that don't use Asian characters much, if at all--in this case, Nigeria.

When you want to soften your conjecture a lot, even to the point that it could be considered a question, you can use でしょうか.

An example with two possible translations:

タイムマシンはいつか発明されるでしょうか。
タイムマシン　は　いつか　はつめい　される　でしょう　か。
Do you think time machines will be invented someday? // I wonder if time machines will be invented someday.
Literally: “time machine + は + someday + invention + be done (=passive of する) + でしょうか.”
Note: We're cover される and other passive verbs in a future N4 lesson.

Unlike "probably" in English, we cannot use でしょう・だろう when talking about predicting our own actions that we can control.

For example, the following sentence doesn't work:

✕ 僕は来週、京都に行くでしょう。
✕ ぼく　は　らいしゅう、 きょうと　に　いく　でしょう。
✕ I’ll probably go to Kyoto next week.
✕ Literally: “I + は + next week, + Kyoto + に + go + でしょう.”

If you wanted to say "I'll probably go to Kyoto next week," you have quite a few grammatical options, most of which we'll be looking at in N4 lessons in the future.

Perhaps the simplest option, though, would be to say:

〇 僕は来週、京都に行きます。
〇 ぼく　は　らいしゅう、 きょうと　に　いきます。
〇 I’m going to go to Kyoto next week.
〇 Literally: “I + は + next week, + Kyoto + に + go.”

What do you think? Do you have a pretty good grasp of でしょう・だろう now?

If not, no worries, because we've already had two lessons on this verb topic.

Let's travel back in time to:

[NDL #89] - This beat is fire, right? - Part IV
[NDL #90] - This beat is fire, right? - Part V

And... you've done it!

No more N5 lessons! Starting next week, we'll be doing N4 lessons on both Monday and Tuesday. Time to level up that grammar, yo.