でしょう・
Said with a falling voice, でしょう is "probably": your guess about something you can't know for sure. With a rising voice it is "right?": you expect the other person to agree. だろう is the plain form.
How to form it
Plain form + でしょう／だろう
行くでしょう, 行かないでしょう, 行ったでしょう, 高いでしょう. A noun or a な-adjective drops だ: 雨でしょう, 静かでしょう (but 雨だったでしょう). でしょう is the polite part, so the word before it stays plain.
Probably or right? The voice tells you
Tomorrow's meeting probably starts at ten.
The voice falls. You are guessing.
Tomorrow's meeting starts at ten, right?
The voice rises. You are checking with someone who knows.
In writing, the rising one usually has a question mark.
Probably
The weather, the future, what someone else is doing. Weather forecasts are full of it.
The roads are crowded, so the bus will probably be a little late.
At this hour, the station is probably not crowded yet.
Since it is Sunday, this shop is probably closed.
Thought to yourself, or written. Spoken on its own, だろう is blunt, and mostly men say it.
In conversation: と思います
Tanaka will probably come.
Sure of itself. In conversation it can sound like a forecaster or a teacher.
I think Tanaka will probably come.
How people usually give a guess.
たぶん, "probably", often goes in front. Alone, たぶん。 is an answer.
I think it will probably rain tomorrow.
Not for your own plans
Sounds odd: 私は
I will probably go to Kyoto tomorrow.
What you have decided isn't a guess. For a plan, 行きます; if you aren't sure, たぶん行くと思います.
Right?
You think you are right, and the other person can tell you so: they know the fact, or they can see, taste or feel the same thing.
This soup is a little spicy, isn't it?
The meeting ended at three, right?
It's quiet here, right?
だろ and だろう are rough, and mostly men say them.
This cake is good, isn't it?
B chose the cake. Alone, でしょ？ is a pleased "see?".
It expects a yes
So it can sound pushy to a teacher, a boss or a customer.
The test is next week, right?
As if you were telling the teacher.
The test is next week, isn't it?
ですよね checks the same thing without pressing.
I told you so, didn't I?
Said sharply, it scolds. A parent, to a child.
Close neighbours
でしょうかN4
With か, a softer and more polite way to ask a question.
Where will the next information session be held?
Check yourself
1A friend is eating the curry you made. You say this with a rising voice. What do you mean?
この
Choose an answer to see why.
2Which one is right?
Choose an answer to see why.
3You have booked your flight home for next month. Which one do you say?
Choose an answer to see why.
More detail
でしょうね
With ね, a guess about how things are for the other person sounds warm.
I have three exams next week.
That must be tough.
であろう
In formal writing だろう becomes であろう.
This trend will probably continue.
More sentences
Tomorrow it will probably start raining in the afternoon.
The preparation is thorough, so the presentation will probably go well.
The lights are on, so Tanaka is probably still at the office.
With rain like that, yesterday's game was probably canceled.
That restaurant yesterday was inexpensive, wasn't it?
You can see well from this seat, can't you?
You saw this photo too, right?
You returned the key to reception, right?