Jeżeli moja pensja się nie zmieni, poproszę o podwyżkę po wakacjach.

Yes. Jeżeli and jeśli both mean if.

• jeśli is usually more common in everyday speech
• jeżeli can sound a bit more formal or careful

So this sentence could also be:

Jeśli moja pensja się nie zmieni, poproszę o podwyżkę po wakacjach.

Both are correct.

Because Polish normally uses a comma to separate a subordinate clause from the main clause.

Here the first part is the if-clause:

Jeżeli moja pensja się nie zmieni

and the second part is the main clause:

poproszę o podwyżkę po wakacjach

So the comma is required in standard Polish punctuation.

Yes. You can say:

Jeżeli moja pensja się nie zmieni, to poproszę o podwyżkę po wakacjach.

That to is optional. It often makes the connection between the two parts sound a little clearer or more conversational, a bit like then in English. But the version without to is completely normal and natural.

Moja pensja means my salary.

You often can omit possessive words in Polish when the meaning is obvious from context, but here moja sounds natural and clear. It makes it explicit that you are talking about your own salary, not salaries in general.

Without moja, pensja would just mean salary / the salary, and the sentence might sound less specific.

Because the verb here is zmienić się, which means to change in the sense of to become different.

This is different from zmienić coś, which means to change something.

Compare:

• Zmienię pracę. = I will change my job.
• Moja pensja się zmieni. = My salary will change.

So się is needed because the salary is not changing something else; the salary itself is changing.

This is a very important Polish point: zmienić się is a perfective verb.

In Polish, the present-tense forms of perfective verbs usually refer to the future.

So:

• zmieni się = will change
• nie zmieni się = will not change

That is why Jeżeli moja pensja się nie zmieni means If my salary doesn’t change / won’t change in the future.

It is not a true present meaning here.

Yes. Poproszę is the future meaning of the perfective verb poprosić.

Here it means:

I will ask for

So:

poproszę o podwyżkę = I will ask for a raise

A useful comparison:

• prosić = imperfective, to ask / to be asking
• poprosić = perfective, to ask once / to make the request

Because this sentence is about one future action, poproszę is the natural choice.

Because Polish usually shows future meaning through the verb form itself, not with a separate word like English will.

In this sentence:

• zmieni already means will change
• poproszę already means I will ask

So Polish does not need an extra helper word equivalent to English will.

Because the verb prosić / poprosić o requires the noun after o to be in the accusative case.

The basic dictionary form is:

• podwyżka = raise, pay rise

But after o with prosić / poprosić, it changes to accusative:

• o podwyżkę

So:

• podwyżka = nominative
• podwyżkę = accusative

This is just normal case grammar after this verb pattern.

Because po in the meaning after takes the locative case.

The noun wakacje is a plural-only noun in Polish, so its forms are plural.

Here are the relevant forms:

• wakacje = holidays / vacation
• po wakacjach = after the holidays / after vacation

So the ending changes because of the preposition po.

It depends on context.

In Polish, wakacje very often means the summer holiday period, especially the long summer break. So po wakacjach can often suggest after the summer holidays.

But it can also simply mean after vacation in a more personal sense.

So the phrase is flexible, and context tells you which meaning is intended.

Polish word order is more flexible than English word order.

The original sentence is neutral and natural:

Jeżeli moja pensja się nie zmieni, poproszę o podwyżkę po wakacjach.

But you could also say:

Jeżeli moja pensja się nie zmieni, po wakacjach poproszę o podwyżkę.

This puts a bit more focus on po wakacjach.

The meaning stays basically the same, but the emphasis changes slightly.

Because jeżeli introduces a real or open condition: something that may actually happen.

So this sentence means:

If my salary doesn’t change, I’ll ask for a raise after the holidays.

That is a realistic plan.

Gdyby is used for a more hypothetical or less direct condition, and it usually goes with a conditional form:

Gdyby moja pensja się nie zmieniła, poprosiłbym o podwyżkę po wakacjach.

That means something more like:

If my salary didn’t change, I would ask for a raise after the holidays.

So jeżeli is right for a normal future possibility; gdyby would make it more hypothetical.

They are different kinds of salary-related words:

• pensja = salary, regular pay
• podwyżka = raise, pay rise, increase in salary

So the sentence is saying:

• if the existing salary does not change,
• then the speaker will ask for a raise

A related word you may also see is wynagrodzenie, which is a more formal word for pay / remuneration.