Nasz pies szczeka, kiedy słyszy dzwonek do drzwi, ale kot wtedy tylko patrzy przez okno.

Because nasz has to agree with pies in gender, number, and case.

• pies is masculine singular
• it is the subject of the sentence, so it is in the nominative
• therefore the correct form is nasz

Compare:

• nasz pies = our dog
• nasza kotka = our female cat
• nasze okno = our window

Polish does not have articles like English the and a/an. So:

• pies can mean a dog or the dog
• kot can mean a cat or the cat
• dzwonek can mean a bell or the bell / doorbell

The exact meaning depends on context. That is very normal in Polish.

szczeka is the 3rd person singular present tense form of szczekać = to bark.

So:

• ja szczekam = I bark
• ty szczekasz = you bark
• on/ona/ono szczeka = he/she/it barks

Here it matches pies, so nasz pies szczeka = our dog barks / is barking.

It can mean either, depending on context.

Polish present tense often covers both:

• Our dog barks = general habit
• Our dog is barking = happening now

In this sentence, because of the full context, it can sound like a regular reaction: the dog barks when it hears the doorbell.

Because słyszeć means to hear, while słuchać means to listen.

• słyszeć = hearing happens
• słuchać = someone listens on purpose

So:

• pies słyszy dzwonek = the dog hears the doorbell
• pies słucha dzwonka would mean the dog is listening to the bell

In this sentence, the dog is reacting to a sound it hears, so słyszy is the natural choice.

Polish often leaves out subject pronouns when they are clear from the verb form or context.

Here:

• szczeka already tells you the subject is he/she/it
• the previous subject is nasz pies
• so kiedy słyszy dzwonek naturally means when it hears the doorbell

Polish uses pronouns like on, ona, ono only when needed for emphasis, contrast, or clarity.

kiedy means when here.

It introduces a time clause:

• kiedy słyszy dzwonek do drzwi = when it hears the doorbell

In sentences like this, kiedy can often feel like whenever in English, especially if it describes a repeated situation:

• Pies szczeka, kiedy słyszy dzwonek. = The dog barks when/whenever it hears the bell.

Yes, literally it is something like bell for the door or bell to the door, but as a fixed phrase dzwonek do drzwi means doorbell.

Breakdown:

• dzwonek = small bell, bell
• do
  • genitive often means for, to, or shows relation
• drzwi = door

So dzwonek do drzwi is the normal Polish way to say doorbell.

Yes. drzwi is a plural-only noun in Polish. It means door/doors, but in everyday use it often corresponds to singular English door.

So:

• drzwi = door / doors
• do drzwi = to the door / for the door

This is just one of those nouns you learn as naturally plural in Polish, like:

• nożyczki = scissors
• spodnie = trousers

After do, Polish normally uses the genitive case.

So in dzwonek do drzwi:

• do requires the genitive
• drzwi is the genitive form here

With drzwi, the form looks the same as the base dictionary form, which can be confusing. But grammatically, it is functioning as genitive after do.

Because kot is also the subject of its clause, so it stays in the nominative case.

The sentence has two main parts:

• Nasz pies szczeka...
• ale kot wtedy tylko patrzy przez okno.

In the second part, kot is doing the action (patrzy), so nominative is correct.

wtedy means then, at that time, or in that situation.

Here it refers back to the moment when the dog hears the doorbell:

• ale kot wtedy tylko patrzy przez okno = but the cat then / at that moment only looks out the window

It helps connect the second part to the first and makes the contrast clearer.

tylko means only / just, and its position shows what it is emphasizing.

Here:

• kot wtedy tylko patrzy przez okno

This means the cat only / just looks out the window. In other words, that is all it does.

If you move tylko, the emphasis can shift slightly. Polish word order is flexible, but placement often affects nuance.

Because przez normally takes the accusative case.

• okno is a neuter noun
• for many neuter singular nouns, nominative and accusative look the same
• so okno is correct after przez

oknem is the instrumental form, so it would not be used after przez here.

It literally means looks through the window, but in natural English this is often translated as looks out the window.

So:

• patrzeć przez okno = to look through/out of the window

The Polish phrase is completely normal and idiomatic.

Not completely. Polish word order is more flexible than English because case endings and verb forms carry a lot of grammatical information.

This sentence is natural as written:

• Nasz pies szczeka, kiedy słyszy dzwonek do drzwi, ale kot wtedy tylko patrzy przez okno.

But some parts could be moved for emphasis, especially in the second clause. For example:

• ale wtedy kot tylko patrzy przez okno
• ale kot tylko wtedy patrzy przez okno

These versions would not all mean exactly the same thing in emphasis, but they are grammatically possible.

The original version sounds natural and clearly contrasts the dog’s reaction with the cat’s reaction.

By itself, kot just means cat. Since Polish has no articles, context decides whether English should use a or the.

In this sentence, because we already have our dog and then a contrasting cat, English would usually interpret it as the cat or possibly our cat, depending on the wider context.

Polish does not have to spell that out unless the speaker wants to. If needed, they could say:

• nasz kot = our cat
• ten kot = that cat / this cat

Because Polish punctuation rules require commas in these places.

• A clause introduced by kiedy is separated by a comma.
• ale = but, and coordinating conjunctions like this are also normally preceded by a comma.

So the commas are not optional stylistic choices here; they are standard Polish punctuation.