Learn Hardcore Polish: Każdy ma swój śpiwór w namiocie, żeby było cieplej w nocy. - Everyone has their own sleeping bag in the tent so that it is warmer at night.

Każdy ma swój śpiwór – Each person has their own sleeping bag (the sleeping bag belongs to that same “each person”).
Każdy ma jego śpiwór – Each person has his sleeping bag (they all have the sleeping bag of some other male person previously mentioned).
Każdy ma ich śpiwór – Each person has their (some group’s) sleeping bag (all have sleeping bags belonging to some other group).

Rule of thumb: if in English you would say one’s own X and the “one” is the subject, Polish strongly prefers swój (or its inflected forms) rather than mój / twój / jego / jej / nasz / wasz / ich.

Why is it Każdy ma (3rd person singular) and not Każdy mają (3rd person plural)?

Grammatically, każdy (each, everyone) is singular, so the verb must also be singular:

Każdy ma śpiwór. – Everyone has a sleeping bag.

This matches English grammar (formal English: everyone has, not everyone have).

If you really want a plural subject, you switch to wszyscy:

Wszyscy mają śpiwory. – All (of them) have sleeping bags.

Could we say Wszyscy mają swoje śpiwory w namiocie, żeby było cieplej w nocy instead? What’s the difference?

Yes, that’s correct, but slightly different in nuance:

Każdy ma swój śpiwór… – looks at people one by one: each person has their own sleeping bag.
Wszyscy mają swoje śpiwory… – looks at the group as a whole: all of them have their sleeping bags.

Grammar changes:

Każdy (singular) → ma (singular) → swój śpiwór (singular).
Wszyscy (plural) → mają (plural) → swoje śpiwory (plural).

Why is it śpiwór, not some other form like śpiwora or śpiworem?

Śpiwór is masculine inanimate. Here it is the direct object of ma (has), so it’s in the accusative.

For masculine inanimate nouns, accusative = nominative:

nominative: śpiwór jest nowy – the sleeping bag is new
accusative: mam śpiwór – I have a sleeping bag

Other forms you might see:

śpiwora – genitive singular (e.g. nie mam śpiwora – I don’t have a sleeping bag)
śpiworem – instrumental singular (e.g. idę ze śpiworem – I’m going with a sleeping bag)

Why is it w namiocie and not w namiot or w namiotu?

The preposition w with the meaning “in / inside (where?)” takes the locative case.

namiot (tent) – nominative
w namiocie – locative: in the tent

Other examples: w domu, w szkole, w pracy.

You may sometimes see w + accusative with a direction (where to?), but with namiot people normally say do namiotu (into the tent), not w namiot in everyday speech.

Why is there a comma before żeby?

Żeby introduces a subordinate clause of purpose (“so that …”). In Polish, you normally put a comma before conjunctions that start subordinate clauses:

…, żeby było cieplej w nocy.
Idę do sklepu, żeby kupić chleb.

So the comma is required here by standard punctuation rules.

Why is it żeby było cieplej and not żeby jest cieplej or żeby będzie cieplej?

After żeby you use a special form built from the past tense form of the verb, even though the meaning is not past. You do not use the normal present/future forms:

correct: żeby było cieplej
incorrect: *żeby jest cieplej, *żeby będzie cieplej

This żeby + past form works like a kind of Polish “subjunctive” or “so that it (will / would) be”:

Otwórz okno, żeby było chłodniej. – Open the window so that it is / will be cooler.
Każdy ma śpiwór, żeby było cieplej. – Everyone has a sleeping bag so that it is / will be warmer.

So było here doesn’t really mean past; it’s the required form after żeby.

What exactly does żeby mean here? Is it “so that” or “in order to”?

In this sentence żeby introduces a purpose:

…, żeby było cieplej w nocy.

English equivalents:

so that it is warmer at night
so that it will be warmer at night
in order for it to be warmer at night
more literally: so that it would be warmer at night

So here żeby is close in meaning to “so that / in order that”.
A near-synonym in Polish is aby: …, aby było cieplej w nocy.

Why is there no explicit word for “it” in żeby było cieplej?

Polish usually does not use a dummy subject like English “it” in sentences about weather, temperature, general states, etc.:

Jest zimno. – It is cold.
Było gorąco. – It was hot.
Będzie ciekawie. – It will be interesting.

Similarly:

żeby było cieplej – so that it is warmer

The verb było just stands there without a pronoun. Polish doesn’t need to or ono here; adding them would sound wrong or at least very strange in this construction.

What is cieplej exactly? Is it an adjective or an adverb, and how does it relate to ciepły?

Cieplej is the comparative adverb form related to ciepły (warm).

Basic pattern:

adjective (positive): ciepły – warm (a warm day)
adjective (comparative): cieplejszy – warmer (a warmer day)
adverb / predicative (positive): ciepło – warmly / warm (jest ciepło – it is warm)
adverb / predicative (comparative): cieplej – more warmly / warmer (jest cieplej – it is warmer)

In żeby było cieplej, cieplej describes the general state (how it is), so it’s the adverbial/predicative comparative. A longer, more literal but less natural version would be żeby było bardziej ciepło, but native speakers strongly prefer cieplej.

Can I change the word order in żeby było cieplej w nocy? For example, say żeby w nocy było cieplej?

Yes. Several orders are possible and grammatical, with only small shifts of emphasis:

…, żeby było cieplej w nocy. – neutral.
…, żeby w nocy było cieplej. – slight emphasis on at night.
…, żeby było w nocy cieplej. – also possible, similar nuance.

Polish word order is relatively flexible, especially inside subordinate clauses. The key elements (żeby, było, cieplej, w nocy) just need to stay together in one clause; their internal order can vary for rhythm or emphasis.

Why is it w nocy and not nocą or na noc?

All of these exist, but they’re used a bit differently:

w nocy – literally in the night, meaning “at night” (time when something happens).
- Śpimy w namiocie w nocy. – We sleep in the tent at night.
nocą – an adverb, also “at night”, a bit more literary/compact.
- Nocą jest zimniej. – At night it is colder.
na noc – roughly “for the night”, focusing on the period you’re preparing for.
- Zostawiliśmy światło na noc. – We left the light on for the night.

In this sentence w nocy simply answers “when is it warmer?” – at night.
You could say …, żeby nocą było cieplej, but w nocy is more neutral and very common.

Could we say Każdy ma śpiwór w namiocie without swój? Does it change the meaning?

Yes, you can say:

Każdy ma śpiwór w namiocie.

This would usually still be understood as everyone has a (their) sleeping bag in the tent, but it doesn’t explicitly stress ownership. Adding swój clearly says their own sleeping bag and makes that idea explicit.

So:

Każdy ma śpiwór… – neutral: each person has a sleeping bag.
Każdy ma swój śpiwór… – emphasises that each person has their own sleeping bag (not sharing one, not someone else’s).

How could I say explicitly “so that we are warmer” in Polish, using this structure?

You can add a dative pronoun to show who should feel warmer:

Każdy ma swój śpiwór w namiocie, żeby nam było cieplej w nocy.
– Everyone has their own sleeping bag in the tent so that we are warmer at night.

Other persons:

…, żeby mi było cieplej. – so that I am warmer.
…, żeby wam było cieplej. – so that you (plural) are warmer.
…, żeby im było cieplej. – so that they are warmer.

The structure is: żeby + (dative pronoun) + było cieplej.