Dzieci dostają po jabłku.

In this sentence, po does not mean after. It has a distributive meaning: one each, apiece.

So Dzieci dostają po jabłku means:

• The children get an apple each
• The children are receiving one apple each

This use of po is very common in Polish when something is given separately to each person.

Because after po in this one-each/apiece meaning, Polish uses the locative singular.

• basic form: jabłko
• locative singular: jabłku

So:

• po jabłku = one apple each

Even though English would just say an apple each, Polish shows this with po + a special case form.

Because the sentence means that each child gets one apple, not that the children get apples as one shared mass.

Polish expresses that idea by using:

• a plural receiver: dzieci = children
• but a singular distributed item: po jabłku = one apple each

So the singular is important. It shows the item is counted per person.

Dzieci is the nominative plural form of dziecko (child).

This is an irregular plural, so it does not look like the singular very much:

• dziecko = child
• dzieci = children

In this sentence, dzieci is the subject, so nominative plural is exactly what we expect.

Dostają is the 3rd person plural present tense of the imperfective verb dostawać (to get, to receive).

Because the subject is plural (dzieci), the verb is also plural:

• dziecko dostaje = the child gets
• dzieci dostają = the children get

This present tense can mean different things in English depending on context:

• The children get an apple each — habitual/general
• The children are getting an apple each — happening now

The verb dostawać is imperfective, so dostają works well for:

• repeated actions
• general situations
• something in progress

So this sentence can describe a routine, for example at school or at lunch.

If you wanted a more clearly single completed future event, Polish would often use the perfective verb dostać:

• Dzieci dostaną po jabłku = The children will get an apple each

So dostają is natural if the sentence is about what usually happens or what is happening now.

You could say it, but it usually would not mean the same thing.

• Dzieci dostają po jabłku = each child gets one apple
• Dzieci dostają jedno jabłko = the children get one apple

The second version sounds like there is one apple total for the children as a group.

So if you want to make one each clear, po jabłku is the natural Polish way.

Yes, the idea is similar, but the structure is different.

For example:

• Każde dziecko dostaje jabłko = Each child gets an apple
• Dzieci dostają po jabłku = The children get an apple each

Both express distribution, but po jabłku is a very compact and natural way to say one each after a plural subject.

Yes, Polish word order is flexible, but Dzieci dostają po jabłku is the most neutral order.

You may also hear things like:

• Po jabłku dostają dzieci

That is grammatically possible, but it sounds more marked and puts extra focus on po jabłku.

For a learner, the safest and most natural version is:

• Dzieci dostają po jabłku