Muszę kupić nowy guzik, bo bez niego ta koszula wygląda źle, a zamek nadal nie działa dobrze.

Because Polish often drops subject pronouns when the verb ending already shows who is doing the action.

• muszę = I must / I have to
• the ending -ę already tells you it is 1st person singular

So:

• Muszę kupić = I have to buy
• Ja muszę kupić is also possible, but ja adds emphasis, like I have to buy it.

Also, musieć is followed by an infinitive:

• muszę kupić = I must buy
• literally: must + to buy

Because guzik is the direct object of kupić, so it goes in the accusative case.

However, for a masculine inanimate noun like guzik, the accusative singular is the same as the nominative singular:

• nominative: nowy guzik
• accusative: nowy guzik

So even though it is an object, the form does not change.

Compare:

• Widzę nowy guzik. = I see a new button.
• To jest nowy guzik. = This is a new button.

Same form, different function.

Here, guzik means button on a piece of clothing.

In this sentence it refers to a shirt button:

• Muszę kupić nowy guzik = I have to buy a new button

A learner may notice that Polish clothing vocabulary can be tricky because several fastening words exist:

• guzik = button
• zamek = zipper / zip / lock
• napa = snap / press-stud

So this sentence mentions two different clothing problems:

• a missing or damaged button
• a zipper that still does not work properly

After the preposition bez (without), Polish uses the genitive case.

So:

• on / ono = he / it
• genitive form after bez = niego

That gives:

• bez niego = without him / without it

Here it refers to guzik, so in English we translate it as without it.

This is a very common pattern:

• bez cukru = without sugar
• bez problemu = without a problem
• bez niego = without it / him

In Polish, pronoun forms are based on grammatical gender, not only natural gender.

The noun guzik is masculine, so the pronoun used for it matches masculine forms:

• guzik → on
• after bez → niego

Even though guzik is a thing, Polish still uses the same grammatical form that can also mean him in other contexts.

So:

• bez niego can mean without him
• but here, because the noun is guzik, it means without it

Context tells you which one is meant.

Because ta koszula is the subject of wygląda.

• ta koszula wygląda źle = this shirt looks bad

The subject is in the nominative case:

• ta koszula = nominative

If it were a direct object, you would use the accusative:

• Widzę tę koszulę. = I see this shirt.

So:

• ta koszula = subject
• tę koszulę = object

Because źle is an adverb, and with wyglądać Polish often uses an adverb to describe appearance or the overall impression.

• wygląda źle = looks bad
• literally: looks badly / poorly, but in natural English it means looks bad

This does not mean the shirt is morally bad. It means it looks wrong, unattractive, damaged, incomplete, etc.

Compare:

• Koszula wygląda źle. = The shirt looks bad.
• To jest zła koszula. = This is a bad shirt.

The first is about appearance in this situation. The second is about the shirt being bad in a more general sense.

Yes, zamek has several meanings in Polish. It can mean:

• castle
• lock
• zipper / zip

Here, because the sentence is about a shirt, zamek means zipper.

So:

• zamek nadal nie działa dobrze = the zipper still doesn’t work well

This is a good example of how context decides the meaning.

Nadal means still. In Polish, it commonly appears before the verb or before the whole verbal phrase.

So:

• zamek nadal nie działa dobrze = the zipper still doesn’t work well

This word order is very natural.

You could also hear slightly different word orders for emphasis, but this version is standard and neutral.

Breaking it down:

• zamek = the zipper
• nadal = still
• nie działa = does not work
• dobrze = well

Both are possible, but they mean slightly different things.

• nie działa = it doesn’t work
• nie działa dobrze = it doesn’t work well

The second version suggests the zipper may function a little, but poorly, unreliably, or not smoothly.

So the sentence gives a more specific idea: the zipper is still not working properly, rather than being completely unusable.

A is a very common Polish conjunction used to connect two related statements, often with a slight contrast or shift.

Here it works well because the speaker is mentioning another problem with the shirt:

• bo bez niego ta koszula wygląda źle, a zamek nadal nie działa dobrze

This is like:

• ..., and the zipper still doesn’t work well
• or ..., while the zipper still doesn’t work well

Why not the others?

• i = plain and, just simple addition
• ale = but, stronger contrast
• a = a softer contrast or a transition to another related point

So a sounds very natural here.

There are commas because the sentence contains multiple clauses.

The full sentence is:

• Muszę kupić nowy guzik, bo bez niego ta koszula wygląda źle, a zamek nadal nie działa dobrze.

Why the commas?

1. Before bo

   • bo = because
   • It introduces a subordinate clause, so Polish normally uses a comma before it.

2. Before a

   • a links another clause, so a comma is also used.

So the sentence is divided like this:

• Muszę kupić nowy guzik
• bo bez niego ta koszula wygląda źle
• a zamek nadal nie działa dobrze

Yes. Kupić is the perfective verb, meaning to buy as a completed action.

• kupić = buy, complete the purchase
• kupować = buy / be buying / buy repeatedly

In this sentence, the speaker means a single completed action is needed:

• Muszę kupić nowy guzik. = I need to buy a new button.

That is why kupić is the natural choice.

If you used kupować, it would sound more like an ongoing or repeated action, which does not fit as well here.

Not very naturally. A close literal breakdown is:

• Muszę = I must / I have to
• kupić = buy
• nowy guzik = a new button
• bo = because
• bez niego = without it
• ta koszula = this shirt
• wygląda źle = looks bad
• a = and / while / but
• zamek nadal nie działa dobrze = the zipper still does not work well

A natural English translation would be:

• I have to buy a new button, because without it this shirt looks bad, and the zipper still doesn’t work well.

So the Polish structure is fairly close to English, but some parts, especially bez niego and wygląda źle, are better understood as natural phrases rather than translated word by word.