Ten chłopiec czeka przed szkołą na swoją siostrę.

Not exactly. Polish does not have articles like the or a.

Here, ten means this:

• ten chłopiec = this boy

If you remove ten, the sentence still works:

• Chłopiec czeka przed szkołą na swoją siostrę. = The/A boy is waiting in front of the school for his sister.

So ten is used when you want to point out a specific boy, like this boy.

Because chłopiec is the subject of the sentence, and subjects normally go in the nominative case in Polish.

• chłopiec = nominative singular
• chłopca = accusative or genitive singular, depending on context

In this sentence, the boy is the one doing the action of waiting, so nominative is required:

• Ten chłopiec czeka... = This boy is waiting...

Czeka is the 3rd person singular present tense form of the verb czekać (to wait).

Conjugation:

• ja czekam = I wait / am waiting
• ty czekasz = you wait
• on / ona / ono czeka = he / she / it waits

So:

• Ten chłopiec czeka = This boy is waiting

In Polish, the present tense often covers both English waits and is waiting, depending on context.

Because the preposition przed takes different cases depending on meaning.

Here it means in front of, so it expresses location, and that requires the instrumental case.

• szkoła = school (dictionary form, nominative)
• szkołą = instrumental singular

So:

• przed szkołą = in front of the school

This is a very common pattern:

• przed domem = in front of the house
• przed sklepem = in front of the shop

It can mean both, depending on context.

1. Spatial meaning: in front of

   • przed szkołą = in front of the school

2. Time meaning: before

   • przed obiadem = before lunch
   • przed lekcją = before class

In your sentence, because it talks about a person waiting by a place, the meaning is clearly in front of.

Because in Polish, the verb czekać usually goes with the preposition na when you mean to wait for someone or something.

So the pattern is:

• czekać na + accusative

Examples:

• czekam na autobus = I’m waiting for the bus
• czekamy na nauczyciela = we’re waiting for the teacher
• czeka na swoją siostrę = he’s waiting for his sister

This is just something you need to learn together with the verb, like a fixed pattern.

Because na after czekać requires the accusative case.

• siostra = nominative
• siostrę = accusative singular

So:

• na swoją siostrę = for his sister

This is an important thing to notice: the noun changes because of the preposition and the verb pattern.

Because Polish often uses the reflexive possessive swój when the possessor is the same as the subject.

Here:

• the subject is ten chłopiec
• the sister belongs to that same boy

So Polish prefers:

• na swoją siostrę = waiting for his own sister

Using jego siostrę is grammatically possible in some contexts, but it can sound less natural here and may suggest someone else’s sister, depending on context.

This is a very important Polish pattern:

• Jan kocha swoją matkę. = Jan loves his own mother.
• Jan kocha jego matkę. = Jan loves his mother, possibly someone else’s mother.

So swoją is the normal choice here.

Swoją is the accusative singular feminine form of swój.

It has to match siostrę, because siostrę is:

• singular
• feminine
• accusative

So the adjective/pronoun must match it:

• swoja would be wrong here
• swoją siostrę is correct

This is agreement:

• noun and modifier match in gender, number, and case

Yes. Polish word order is more flexible than English because case endings show grammatical relationships.

The neutral order here is:

• Ten chłopiec czeka przed szkołą na swoją siostrę.

But other orders are possible, for example:

• Przed szkołą ten chłopiec czeka na swoją siostrę.
• Na swoją siostrę ten chłopiec czeka przed szkołą.

These versions can change the focus or emphasis, but the basic meaning stays similar.

English relies heavily on word order. Polish relies much more on endings, so speakers can move words around more freely.

Yes, czekać is an imperfective verb.

That makes sense because waiting is usually seen as:

• ongoing
• not completed
• in progress

In this sentence, the boy is in the middle of waiting, so the imperfective verb is the natural choice.

Polish aspect is very important, but here you can simply think:

• czekać = to be waiting / to wait (ongoing situation)

There is no simple perfective partner used in the same everyday way for this sentence.

These nasal vowels are often tricky for English speakers.

• ą in szkołą
• ę in siostrę

In careful pronunciation, they are nasal vowels. But in normal speech, their pronunciation often depends on what comes next.

Very roughly:

• szkołą sounds something like shko-won / shko-łom depending on accent and context
• siostrę often sounds close to sho-struh or shos-tren in connected speech, though the exact sound varies

A few extra pronunciation notes:

• sz = English sh
• ch = like a strong h sound
• ł = English w
• cz = like ch in chop
• ę at the end of a word is often pronounced less strongly nasally in everyday speech

A rough beginner-friendly pronunciation of the whole sentence could be:

Ten hwo-pyets CHE-ka pshet SHKO-won na SVO-yon SHO-struh

That is only approximate, but it helps as a starting point.

Yes, you can.

• czeka na siostrę = he is waiting for a sister / his sister / the sister, depending on context
• czeka na swoją siostrę = he is waiting for his own sister

Including swoją makes the meaning more specific and explicit. Without it, the sentence is still grammatical, but slightly less detailed.

Exactly—they do different jobs.

• przed szkołą tells you where the waiting happens
• na swoją siostrę tells you who he is waiting for

So the sentence structure is:

• Ten chłopiec = subject
• czeka = verb
• przed szkołą = place/location
• na swoją siostrę = object of waiting

This is very common in Polish: one phrase gives location, another gives the target of the action.

Yes, very natural.

It sounds like a normal everyday sentence. A Polish speaker would easily say or understand it.

A few equally natural variants are:

• Ten chłopiec czeka na swoją siostrę przed szkołą.
• Chłopiec czeka przed szkołą na swoją siostrę.

The original version is fully correct and idiomatic.