Kada je hladno, nosim kaput i čarape.

Yes. Kada means when, and kad is a very common shorter form.

So these are both natural:

• Kada je hladno, nosim kaput i čarape.
• Kad je hladno, nosim kaput i čarape.

In everyday speech, kad is often more common. Kada can sound a bit more neutral or slightly more formal.

Je is the 3rd person singular present form of biti (to be).

Serbian often uses an impersonal structure here:

• hladno je = it is cold

There is no word for it in this kind of sentence. English needs it is cold, but Serbian simply says hladno je.

So:

• kada je hladno = when it is cold

Because hladno here is not describing a noun like cold weather or a cold room. It is being used in an impersonal expression meaning it is cold.

In these weather/condition expressions, Serbian often uses the neuter singular adverb-like/predicative form:

• hladno je = it is cold
• toplo je = it is warm
• vruće je = it is hot

If you were describing a noun, then you would match gender:

• hladan dan = a cold day
• hladna voda = cold water
• hladno vreme = cold weather

But in je hladno, the form is hladno.

Nosim is the 1st person singular present tense of nositi, meaning to wear or to carry, depending on context.

Here it means I wear:

• nosim = I wear / I carry

Since the verb ending already shows the subject, Serbian usually does not need the pronoun ja.

So:

• Nosim kaput i čarape. = I wear a coat and socks.

You could say Ja nosim..., but that usually adds emphasis, like I wear...

Because Serbian is a language where the verb ending usually tells you who the subject is.

• nosim = I wear
• nosiš = you wear
• nosi = he/she/it wears

So ja is often omitted unless you want emphasis, contrast, or clarity.

Compare:

• Nosim kaput. = I wear a coat.
• Ja nosim kaput, a on nosi jaknu. = I wear a coat, and he wears a jacket.

Yes. They are the direct objects of nosim, so they are in the accusative case.

• kaput is masculine inanimate, and for many masculine inanimate nouns, the accusative looks the same as the nominative:

  • nominative: kaput
  • accusative: kaput

• čarape is the plural accusative form of čarapa:

  • nominative singular: čarapa
  • accusative singular: čarapu
  • nominative/accusative plural: čarape

So in the sentence:

• nosim kaput = I wear a coat
• nosim čarape = I wear socks

Here čarape means socks, so plural is the normal choice, just as in English.

The singular čarapa means sock or stocking, depending on context.

Examples:

• Nosim čarape. = I wear socks.
• Nosim jednu čarapu. = I am wearing one sock.

So in your sentence, plural is natural because people normally wear more than one sock.

Because kada je hladno is a subordinate clause at the beginning of the sentence.

Serbian normally separates that introductory clause with a comma:

• Kada je hladno, nosim kaput i čarape.

This is similar to English:

• When it is cold, I wear a coat and socks.

If the main clause came first, you would usually not need a comma before the subordinate clause in simple sentences like this:

• Nosim kaput i čarape kada je hladno.

Yes, Serbian word order is fairly flexible, though some orders sound more neutral than others.

The most neutral version here is:

• Kada je hladno, nosim kaput i čarape.

You could also say:

• Nosim kaput i čarape kada je hladno.

Both are correct. The first puts more focus on the condition when it is cold. The second starts more directly with I wear...

You can also move items around for emphasis, but beginners should stick to the more neutral patterns first.

For wearing clothes, nositi is the normal verb.

• nositi kaput = to wear a coat
• nositi čarape = to wear socks

Be careful, because nositi can also mean to carry:

• Nosim torbu. = I am carrying a bag. / I carry a bag.

Context tells you which meaning is intended.

For putting clothes on, Serbian uses a different verb:

• obući / oblačiti = to put on / get dressed

So:

• Nosim kaput. = I am wearing a coat.
• Oblačim kaput. = I am putting on a coat.

Yes. In this kind of sentence, kada can often mean when in a general, repeated sense, not just one specific occasion.

So the Serbian sentence naturally works as:

• When it’s cold, I wear a coat and socks.
• Whenever it’s cold, I wear a coat and socks.

If you wanted to make the repeated sense extra clear, context usually does that, but the basic sentence already sounds general and habitual.

Kaput usually means a coat, often a longer or heavier outer garment.
Jakna usually means a jacket.

So:

• Nosim kaput = I wear a coat
• Nosim jaknu = I wear a jacket

In a sentence about cold weather, both could make sense, depending on what you want to say. But kaput is perfectly natural if you mean a coat.

A rough English-style guide would be:

KAH-dah yeh HLAHD-noh, NOH-seem KAH-poot ee CHAH-rah-peh

A few helpful points:

• j in Serbian sounds like English y
• č sounds like ch in church, but a bit firmer
• stress is not marked in normal writing, so learners usually pick it up by listening

The important part is to pronounce each vowel clearly:

• ka-da
• je
• hlad-no
• no-sim
• ka-put
• ča-ra-pe