Dzieci lubią głaskać królika, ale nie głaszczą go, kiedy je.

Because królika is the accusative singular form of królik.

The verb głaskać takes a direct object, so Polish uses the accusative:

• głaskać królika = to pet the rabbit

For masculine animate nouns like królik, the accusative singular usually ends in -a, so it looks like the genitive:

• nominative: królik
• accusative: królika

Go means him/it here and refers back to królika.

Instead of repeating królika, Polish uses the object pronoun:

• nie głaszczą królika
• nie głaszczą go

Both mean the same thing, but the second one avoids repetition.

Even though English would usually say it for a rabbit, Polish follows the noun’s grammatical gender. Since królik is masculine, the pronoun is go.

They are two forms of the same verb: głaskać.

• głaskać = infinitive, to pet
• głaszczą = 3rd person plural present, they pet / they are petting

After lubić, Polish normally uses the infinitive:

• Dzieci lubią głaskać królika = Children like to pet the rabbit

In the second clause, the verb is the main action of the sentence, so it has to be conjugated:

• nie głaszczą go = they do not pet it

Here je is the verb jeść in the 3rd person singular present:

• je = eats / is eating

So kiedy je means when it is eating or when he is eating, depending on context.

It does not mean when they eat, because the 3rd person plural of jeść is jedzą, not je.

This is an important point because je can also be a pronoun in other sentences, but here it is clearly a verb.

Because Polish often omits subject pronouns when the meaning is clear from the verb ending.

The form głaszczą already tells you the subject is they. Since dzieci was already mentioned, Polish does not need to repeat it.

So:

• ale nie głaszczą go = but they do not pet it

You could repeat the noun:

• ale dzieci go nie głaszczą

But that sounds more emphatic or contrastive.

Dzieci is plural. It means children and is the irregular plural of dziecko.

• singular: dziecko = child
• plural: dzieci = children

Because it is plural, it takes plural verb forms:

• dzieci lubią
• dzieci głaszczą

This is just an irregular noun that learners have to get used to.

The sentence uses imperfective verbs because it describes general, repeated, or ongoing actions, not one completed event.

• lubić = to like
• głaskać = to pet, to stroke
• jeść = to eat

The idea is:

• children like doing this in general
• they do not do it while the rabbit is in the middle of eating

A perfective verb such as pogłaskać would suggest a single completed act of petting, which does not fit as naturally here.

Because Polish punctuation normally requires them here.

• A comma usually comes before ale = but
• A comma also comes before a subordinate clause introduced by kiedy = when

So:

• Dzieci lubią głaskać królika, ale...
• ..., kiedy je

This is standard Polish punctuation.

It can mean either, depending on context.

Polish does not have a separate tense like English is eating. The present tense often covers both:

• je = eats
• je = is eating

In this sentence, English naturally uses is eating because the action is happening at that time:

• when it is eating

Yes. Polish word order is more flexible than English, although some versions sound more neutral than others.

The given sentence is natural:

• Dzieci lubią głaskać królika, ale nie głaszczą go, kiedy je.

You could also say:

• Dzieci lubią głaskać królika, ale kiedy je, nie głaszczą go.

That still means the same thing, but it puts more focus on when it is eating.

So the word order can change, but the original version is a normal, natural one.