Nevím, zda přijde.

In Czech, the subject pronoun is often omitted because the verb ending already shows who the subject is.

• nevím = I don't know
• the ending -ím tells you it is I

So Nevím is the normal, natural way to say it.
You can add já for emphasis or contrast:

• Já nevím. = I don't know. / Me, I don't know.

In a neutral sentence, leaving out já is standard.

zda introduces an indirect yes/no clause. In this sentence, it means something like whether or if.

So the structure is:

• Nevím = I don't know
• zda přijde = whether he/she/it will come

This is more formal or bookish than jestli, which is very common in everyday speech.

Yes. That is very common and natural.

• Nevím, zda přijde.
• Nevím, jestli přijde.

Both mean the same thing here. The main difference is style:

• zda = a bit more formal, written, or careful
• jestli = very common in everyday spoken Czech

So as a learner, you will hear jestli a lot, but zda is absolutely correct.

Because zda přijde is a subordinate clause, and Czech normally separates subordinate clauses with a comma.

So:

• Nevím, zda přijde.

This is standard Czech punctuation. English often does not use a comma in the equivalent sentence, but Czech does.

This is a very important Czech grammar point.

The verb přijít is perfective. Perfective verbs do not normally have a true present meaning. Their “present-tense” forms usually express the future.

So:

• přijde literally looks like a present-tense form
• but with a perfective verb, it means he/she will come

Compare:

• chodí = he/she goes, comes regularly, is in the habit of going/coming
• přijde = he/she will come, will arrive

So in this sentence, přijde is the normal way to say will come.

The infinitive is přijít.

This verb means to come or to arrive, often with the sense of completing the action of coming.

Some useful forms:

• přijít = infinitive
• přijdu = I will come
• přijdeš = you will come
• přijde = he/she/it will come

Because it is perfective, these forms usually refer to the future.

Czech often leaves pronouns unstated when they are understood from context.

So přijde can mean:

• he will come
• she will come
• it will come

The exact meaning depends on the situation. Czech speakers usually do not need to state the pronoun unless it is important for clarity or emphasis.

If needed, you could say:

• Nevím, zda on přijde. = I don't know whether he will come.
• Nevím, zda ona přijde. = I don't know whether she will come.

But in a normal sentence, the pronoun is often omitted.

Because Czech forms the future in different ways depending on the type of verb.

For perfective verbs like přijít, the simple present-looking form already has future meaning:

• přijde = will come

The future with bude is used with imperfective verbs:

• bude přicházet = will be coming / will come repeatedly
• bude chodit = will go / will keep going

So bude přijít is not correct here.

Often it is somewhere between come and arrive.

The verb přijít focuses on reaching the destination, so arrive is often a good match. But in many contexts, English naturally says come.

So depending on context, Nevím, zda přijde could match:

• I don't know whether he’ll come.
• I don't know whether she’ll arrive.

The Czech sentence itself does not force one exact English choice.

A simple pronunciation guide:

• Nevím ≈ NEH-veem
• zda ≈ zda with a clear zd cluster
• přijde ≈ roughly PRZHIY-deh

A few notes:

• í is a long vowel: ví
• ř in přijde is the famous Czech sound, something like a mix of r and zh
• j is pronounced like English y
• final e is pronounced, not silent

If ř is difficult, that is completely normal for learners.

Yes, but this order is the most neutral.

• Nevím, zda přijde. = neutral, standard

Because Czech word order is flexible, other versions can appear in context, but they usually add emphasis or sound less neutral. For a learner, this sentence is the best basic pattern to remember:

• Nevím, zda/jestli + clause

Examples:

• Nevím, zda to udělá. = I don't know whether he/she will do it.
• Nevím, jestli tam bude. = I don't know whether he/she will be there.

It is grammatically neutral, but zda makes it sound slightly more formal than everyday casual speech.

So:

• Nevím, zda přijde. = correct, natural, a bit more formal/written
• Nevím, jestli přijde. = very natural, common in speech

Neither is wrong. If you are speaking casually, jestli is often the safer everyday choice.