Nie wiem, czy dojedziemy na czas, bo autobus jest spóźniony.

Because Polish uses wiedzieć for knowing a fact, piece of information, or answer.

• Nie wiem = I don’t know
• Nie znam = I don’t know / am not familiar with a person, place, book, song, etc.

So in this sentence, the speaker does not know whether we will arrive on time, which is information, so wiedzieć is the correct verb.

Examples:

• Nie wiem, gdzie on jest. = I don’t know where he is.
• Nie znam tego człowieka. = I don’t know that man.

Here czy means whether / if in an indirect question.

So:

• Nie wiem, czy dojedziemy na czas
  = I don’t know whether we’ll get there on time

This is different from the if used for conditions in English. In Polish:

• czy = whether / if
• jeśli / jeżeli = if, in the sense of a condition

Compare:

• Nie wiem, czy przyjdzie. = I don’t know whether he’ll come.
• Jeśli przyjdzie, porozmawiamy. = If he comes, we’ll talk.

Dojedziemy comes from dojechać, which means to get to / reach a destination by vehicle.

So dojedziemy is more specific than just jedziemy:

• jedziemy = we are going / we go
• dojedziemy = we will get there / arrive there (by vehicle)

Because the sentence is about whether the bus delay will prevent arrival on time, dojechać is a very natural choice.

It is 1st person plural future: we will arrive / we will get there.

Breakdown:

• infinitive: dojechać
• future form: dojedziemy = we will get there

Polish perfective verbs often form the future with a single word, not with a separate equivalent of will.

Because dojechać is a perfective verb.

In Polish:

• imperfective verbs form the future with będę / będziesz / będzie...
• perfective verbs form the future as a simple one-word form

So:

• będziemy jechać = we will be going / traveling
• dojedziemy = we will arrive / get there

The perfective verb focuses on the completed result: reaching the destination.

Na czas means on time, in time, or by the required time/deadline, depending on context.

In this sentence:

• dojedziemy na czas = we’ll get there on time

It is a fixed expression, so it’s best learned as a whole phrase.

Compare:

• Przyszedł na czas. = He arrived on time.
• Muszę oddać projekt na czas. = I have to submit the project on time.

Bo means because. It is common in everyday spoken and written Polish.

So:

• bo autobus jest spóźniony = because the bus is delayed / late

A more formal alternative would be ponieważ:

• ..., ponieważ autobus jest spóźniony.

But bo is very natural and probably the most common choice in normal conversation.

Yes, spóźniony is often used for people, but it is also very commonly used for transport such as buses, trains, and planes.

So:

• Jestem spóźniony / spóźniona. = I am late.
• Pociąg jest spóźniony. = The train is delayed.
• Autobus jest spóźniony. = The bus is delayed.

In English, we often prefer delayed for transport, but Polish naturally uses spóźniony here.

It is accusative singular: czas.

The preposition na can take different cases depending on meaning, but in the fixed expression na czas, you simply learn the whole phrase as on time.

For the noun czas:

• nominative: czas
• accusative: czas

So the form looks the same here.

Because in Polish, subordinate clauses are normally separated by commas.

This sentence has:

• Nie wiem, czy dojedziemy na czas — an indirect question introduced by czy
• ..., bo autobus jest spóźniony — a clause introduced by bo

So the commas are standard and expected:

• Nie wiem, czy...
• ..., bo...

Polish uses commas more consistently than English in this kind of structure.

No, that would be incorrect here.

Use:

• czy for whether / if
• jeśli / jeżeli for conditional if

Correct:

• Nie wiem, czy dojedziemy na czas. = I don’t know whether we’ll arrive on time.

Conditional:

• Jeśli dojedziemy na czas, zdążymy. = If we arrive on time, we’ll make it.

It is most commonly used when the journey is by some means of transport: car, bus, bike, train, etc.

Examples:

• Dojedziemy autobusem. = We’ll get there by bus.
• Jak dojadę do centrum? = How do I get to the city center?

If you want a more general verb for arrive, Polish also uses:

• dotrzeć = reach, get to
• przyjechać = arrive by vehicle
• przyjść = come on foot

So dojedziemy works especially well here because the sentence is specifically about a bus.

The main stress in Polish is usually on the second-to-last syllable.

Useful approximations:

• Nie wiem → NYEH vyem
• czy dojedziemy → chi do-ye-DZHE-my
• na czas → na chas
• bo autobus jest spóźniony → boh au-TO-boos yest spoz-NYO-ny

A couple of pronunciation notes:

• czy sounds like chy in history, but harder and shorter
• dzi in dojedziemy is a soft sound, roughly j/דזש-like
• spóźniony has a soft ni sound, like nyo

The natural sentence stress would usually fall on the important information, often something like:

• Nie wiem, czy dojedziemy na czas, bo autobus jest spóźniony.

Yes, Polish word order is fairly flexible, but the original order is the most neutral and natural.

Standard version:

• Nie wiem, czy dojedziemy na czas, bo autobus jest spóźniony.

You might also hear:

• Bo autobus jest spóźniony, nie wiem, czy dojedziemy na czas.

That version is possible, but it puts extra emphasis on the reason. For a learner, the original order is the safest choice.