My idziemy do domu, a inni zostają w bibliotece.

Yes—Polish often drops subject pronouns because the verb ending already shows who is doing the action.

• idziemy = we go / we are going
• zostają = they stay / are staying

So my is not strictly necessary here. It is included for emphasis or contrast. In this sentence, it helps create a clear contrast:

• My idziemy do domu = We are going home
• a inni zostają w bibliotece = and others are staying in the library

So my here feels a bit like we, on the other hand...

Because my is the subject pronoun (we), while idziemy is the verb form (we go / we are going). They are different words with different jobs.

The verb comes from iść (to go), and in the present tense:

• idę = I go
• idziesz = you go
• idzie = he/she/it goes
• idziemy = we go
• idziecie = you all go
• idą = they go

So idziemy is simply the correct we form of iść.

It can mean either, depending on context.

In Polish, the present tense often covers both:

• we go
• we are going

So My idziemy do domu could mean:

• We are going home (right now / in this situation)
• We go home (in a more general or scheduled sense)

In this sentence, the most natural reading is probably We’re going home, because it contrasts with what other people are doing at the same time.

Because after do (to, into, toward), Polish normally uses the genitive case.

• dom = house / home
• do domu = to the house / home

So:

• Idziemy do domu = We are going home

This is a very common pattern:

• do szkoły = to school
• do pracy = to work
• do sklepu = to the shop/store

Because domu is the genitive singular form of dom.

The preposition do requires the genitive, so:

• nominative: dom
• genitive: domu

This kind of noun change is very common in Polish. English usually does not change the noun after prepositions, but Polish often does.

Not exactly.

Both a and i can sometimes be translated as and, but they are used differently.

• i simply adds information: and
• a often shows contrast, comparison, or a change of topic: and / while / whereas / but

In this sentence, a is perfect because the two parts are being contrasted:

• We are going home
• while others are staying in the library

So a here feels like:

• and
• while
• whereas

depending on how you translate it.

Inni means others or other people.

It comes from inny, meaning other / different.

Here, inni is in the masculine personal plural nominative form, used for groups of people that include males or are treated as mixed groups.

So:

• inni zostają = others stay / the others are staying

If you are talking about people in a general mixed group, inni is the natural form.

Like idziemy, it can mean either stay or are staying, depending on context.

Here it comes from zostawać / zostać, but in this sentence zostają means they remain / they are staying.

So:

• inni zostają w bibliotece = others are staying in the library

The context suggests an ongoing present situation, so are staying is the most natural English translation.

Because Polish usually does not need subject pronouns when the verb ending already shows the subject.

• zostają already tells us it is they
• the noun inni already functions as the subject: others

So adding a separate pronoun like oni would usually be unnecessary:

• inni zostają = others are staying

You could say oni zostają, but here inni is more specific and more natural.

Because the preposition w (in) usually requires the locative case when it means location.

• biblioteka = library
• w bibliotece = in the library

So the noun changes form after w:

• nominative: biblioteka
• locative: bibliotece

This is another very common Polish pattern:

• w domu = in the house / at home
• w szkole = at school / in school
• w pracy = at work
• w bibliotece = in the library

Usually yes, but sometimes English may prefer at the library, depending on context.

Polish w literally means in, but English often chooses between in and at more flexibly.

So:

• zostają w bibliotece could be translated as
  • they are staying in the library
  • they are staying at the library

The first is more literal; the best choice depends on the situation.

Yes, Polish word order is quite flexible.

The sentence:

• My idziemy do domu, a inni zostają w bibliotece.

is natural and clear, especially because it emphasizes contrast between my and inni.

Other possible word orders include:

• Idziemy do domu, a inni zostają w bibliotece.
• Do domu idziemy, a inni zostają w bibliotece.
• Inni zostają w bibliotece, a my idziemy do domu.

These versions are not identical in emphasis, but they are grammatically possible.

In Polish, word order often changes the focus or emphasis, not the basic meaning.

Most likely a current situation: We’re going home, while others are staying in the library.

However, grammatically, the present tense in Polish can also describe repeated or habitual actions if the context supports that reading.

So without extra context, the sentence is most naturally understood as something happening now or in this situation, especially because the two actions are contrasted side by side.

Yes. In natural English, Idziemy do domu is very often translated as We’re going home, not We’re going to the house.

That is because dom / domu can mean:

• house in some contexts
• home in others

Here, home is clearly the better English choice:

• My idziemy do domu = We’re going home

So the Polish is literally something like we go to home/house, but idiomatic English is simply we’re going home.