W tym zdaniu brakuje przecinka i kropki.

Because the preposition w meaning in requires the locative case when it describes location.

• to zdanie = this sentence in the nominative
• w tym zdaniu = in this sentence in the locative

So:

• to → tym
• zdanie → zdaniu

This is a very common pattern in Polish:

• w domu = in the house
• w sklepie = in the shop
• w zdaniu = in the sentence

Brakuje means is missing, there is a lack of, or is lacking.

In this sentence:

• W tym zdaniu brakuje przecinka i kropki.
• literally: In this sentence, a comma and a period are missing.

It comes from the verb brakować.

A very important thing for learners is that Polish often expresses this idea differently from English. Instead of saying:

• This sentence is missing a comma and a period

Polish naturally says something closer to:

• In this sentence, there lacks a comma and a period

That sounds odd in English, but it is normal in Polish.

Because after brakuje, Polish normally uses the genitive case for the thing that is missing.

Base forms:

• przecinek = comma
• kropka = period / full stop

Genitive forms here:

• przecinka
• kropki

So the structure is:

• brakuje + genitive

More examples:

• Brakuje czasu. = Time is lacking.
• Brakuje cukru. = There is no sugar / sugar is missing.
• Brakuje przecinka. = A comma is missing.

Because both nouns are part of the same phrase governed by brakuje, so both need to be in the genitive.

• przecinka = genitive of przecinek
• kropki = genitive of kropka
• i = and

So:

• brakuje przecinka i kropki = a comma and a period are missing

If one word is controlled by a verb or preposition, coordinated nouns linked by i usually follow the same case requirement.

In this sentence, yes: kropka means the punctuation mark .

Depending on the variety of English, you might translate it as:

• period (American English)
• full stop (British English)

So przecinek i kropka means:

• a comma and a period
• or a comma and a full stop

Yes, absolutely. That is a very natural English translation.

Possible English translations include:

• This sentence lacks a comma and a period.
• A comma and a period are missing from this sentence.
• There is no comma or period in this sentence.
  
  • though this last one can sound slightly broader in meaning

The Polish sentence itself focuses on what is missing in the sentence.

Polish word order is flexible, and starting with w tym zdaniu puts the location or context first: in this sentence.

That makes sense here because the speaker wants to say what is missing from this particular sentence.

You could also hear:

• Brakuje w tym zdaniu przecinka i kropki.

This is still grammatical, but W tym zdaniu brakuje... sounds very natural and often slightly more neutral.

Here are the dictionary forms:

• w = in
• ten = this
• zdanie = sentence
• brakować = to be lacking / to be missing
• przecinek = comma
• i = and
• kropka = period / full stop

And here are the actual forms used in the sentence:

• w
• tym ← from ten
• zdaniu ← from zdanie
• brakuje ← from brakować
• przecinka ← from przecinek
• i
• kropki ← from kropka

Yes. In this construction, brakuje stays in the 3rd person singular form.

Polish does not treat it like a normal plural subject in the way English often would. The sentence is built around the idea of there is a lack of X, and the missing items appear in the genitive.

So even with more than one thing, you can still have:

• Brakuje przecinka i kropki.

This is normal.

Yes, and it is also natural Polish, though the nuance is a little different.

• W tym zdaniu brakuje przecinka i kropki.
  = A comma and a period are missing from this sentence.
  This emphasizes absence as something that should be there.

• W tym zdaniu nie ma przecinka i kropki.
  = There is no comma and period in this sentence.
  This simply states they are not there.

So brakuje often suggests something is missing that ought to be present, which fits very well with punctuation.

A rough pronunciation guide is:

• tym ≈ tim
• zdaniu ≈ ZDA-nyu

A fuller approximation of the whole sentence:

• v tim ZDA-nyu bra-KOO-ye pshe-CHEEN-ka ee KROP-kee

A few helpful notes:

• w is pronounced like English v
• y is not exactly English i, but tim is a useful approximation for tym
• rz in przecinka sounds like the s in measure for many speakers, though in this word the cluster is best learned as a whole
• -uje in brakuje sounds roughly like -ooye

The sentence uses three important parts:

1. w tym zdaniu → locative

   • because of the preposition w meaning in

2. brakuje → verb

   • it governs the genitive for what is missing

3. przecinka i kropki → genitive

   • because they are the things missing

So the case pattern is:

• w + locative
• brakuje + genitive

This is a very useful structure to remember because it appears often in Polish.