Moja majka kaže da bez toplog pokrivača ne može dobro spavati zimi.

Moja majka is the correct nominative singular form, used because majka is the subject of the sentence.

• moja = my (feminine singular nominative)
• majka = mother

The adjective/pronoun moja has to agree with majka in:

• gender: feminine
• number: singular
• case: nominative

So moja majka means my mother.

Both mean mother/mom, but they differ in tone.

• majka = more neutral, standard, sometimes slightly formal
• mama = more affectionate, everyday mom/mum

So this sentence sounds a bit more neutral or standard with majka. In everyday speech, many people would naturally say moja mama instead.

Kaže is the 3rd person singular present tense of kazati / reći in the sense of says.

Since the subject is moja majka = my mother, the verb must match she:

• ja kažem = I say
• ti kažeš = you say
• on/ona kaže = he/she says

So:

• Moja majka kaže = My mother says

Here da introduces a subordinate clause, like English that.

• Moja majka kaže da...
• My mother says that...

In Croatian, da is very commonly used after verbs like:

• reći / kazati = to say
• misliti = to think
• znati = to know
• vidjeti = to see

So in this sentence, da connects the main clause and the idea being reported.

Croatian often leaves out subject pronouns when they are already clear from the verb form or context.

So in:

• Moja majka kaže da bez toplog pokrivača ne može dobro spavati zimi.

the subject of ne može is understood to be she, meaning my mother.

Croatian does this much more often than English. English usually needs the pronoun:

• My mother says that she can't sleep well...

But Croatian can simply omit ona because it is understood.

Because the meaning is cannot sleep, not simply does not sleep.

• ne može spavati = cannot sleep
• ne spava = is not sleeping / does not sleep

So:

• ne može dobro spavati = cannot sleep well
• this expresses inability or difficulty
• not just the fact that she doesn’t sleep

This is an important difference.

In Croatian, ne is usually written separately from verbs.

So:

• može = can
• ne može = cannot

This is normal Croatian spelling. English can't is one word with an apostrophe, but Croatian keeps ne separate in most cases.

After the preposition bez (without), Croatian uses the genitive case.

That is why both words change form:

• topli pokrivač = a warm blanket (nominative)
• bez toplog pokrivača = without a warm blanket (genitive)

So:

• bez
  • genitive

This is a very important pattern to remember.

Because the adjective has to agree with pokrivača in case, number, and gender.

Base form:

• topli pokrivač = warm blanket

After bez, the noun goes into the genitive singular:

• pokrivač → pokrivača

So the adjective must also go into genitive singular masculine:

• topli → toplog

That gives:

• bez toplog pokrivača

Because bez requires the genitive, and pokrivač is a masculine noun.

So:

• nominative: pokrivač
• genitive singular: pokrivača

This is a regular pattern for many masculine nouns.

Examples:

• bez šećera = without sugar
• bez kaputa = without a coat
• bez pokrivača = without a blanket

Pokrivač is a general word for something that covers you, often translated as blanket or cover.

Depending on context, Croatian can also use:

• deka = blanket
• pokrivač = cover/blanket/bedcover

In this sentence, blanket is a very natural translation.

Dobro is an adverb meaning well.

It describes how she sleeps:

• spavati = to sleep
• dobro spavati = to sleep well

So:

• ne može dobro spavati = she can't sleep well

Notice that Croatian uses dobro where English uses well, just as:

• dobro govoriti = to speak well
• dobro raditi = to work well

Because it follows the modal verb moći (can / be able to).

This is the normal pattern:

• mogu spavati = I can sleep
• ne može spavati = she cannot sleep

After moći, the next verb usually stays in the infinitive.

So:

• ne može dobro spavati = cannot sleep well

Zimi is the normal Croatian way to say in winter in a general sense.

It functions like a time adverb:

• ljeti = in summer
• zimi = in winter

So:

• dobro spavati zimi = to sleep well in winter

Using u zimi is not the usual standard way to express this idea. Zimi is the natural form here.

Yes, Croatian word order is fairly flexible, although some orders sound more natural than others.

The sentence has:

• ne može dobro spavati zimi

This is natural and clear: cannot sleep well in winter.

You could also hear variations such as:

• zimi ne može dobro spavati
• ne može zimi dobro spavati

But the original version sounds very normal. Croatian often moves words around for emphasis, rhythm, or style.

No, not with the same meaning.

• da = that
  Used after kaže to introduce what someone says.
• jer = because
• ako = if

So:

• Moja majka kaže da... = My mother says that...

If you used jer or ako, the meaning would change completely.

In this sentence, it most naturally means without a warm blanket in a general sense.

Croatian often does not use articles the way English does, because Croatian has no a/an/the. So context decides the meaning.

Here, the phrase sounds indefinite and general:

• she cannot sleep well in winter without a warm blanket

If the speaker wanted to make it strongly definite, the context would usually make that clear rather than an article.

Yes, it is natural and correct.

It has a very normal structure:

• Moja majka kaže = My mother says
• da = that
• bez toplog pokrivača = without a warm blanket
• ne može dobro spavati = cannot sleep well
• zimi = in winter

A native speaker would understand it immediately, and it sounds like standard Croatian.