Learn Hardcore Croatian: Ljeti često nosim sunčane naočale kad je sunce jako. - In summer I often wear sunglasses when the sun is strong.

Because ljeti already carries the meaning “in summer,” you do not say u ljeti. That would sound ungrammatical or at best very strange to a native speaker.

Can I say u ljeto instead of ljeti? Is there a difference?

You can say u ljeto, but it is less common and sounds a bit more formal or literary.

Typical usage:

Ljeti često nosim sunčane naočale.
Very natural, everyday way to say: In summer I often wear sunglasses.
U ljeto često nosim sunčane naočale.
Grammatically correct, but sounds more like something from written style or more careful speech.

In most normal conversation, ljeti is the default choice.

What tense is nosim, and why don’t we say ja nosim?

Nosim is:

present tense
1st person singular
of the verb nositi (to wear, to carry)

Croatian very often drops the subject pronoun (ja, ti, on, etc.) because the verb ending already shows who the subject is.

Nosim sunčane naočale.
= I wear sunglasses.

Adding ja is only for emphasis or contrast:

Ja nosim sunčane naočale, ali ti ne.
I wear sunglasses, but you don’t.

Why do we use nosim here instead of imam for “I have / I am wearing”?

In Croatian, clothing and accessories that you’re wearing are usually expressed with nositi:

nositi jaknu – to wear a jacket
nositi šešir – to wear a hat
nositi sunčane naočale – to wear sunglasses

The verb imati (to have) talks about possession, not wearing:

Imam sunčane naočale.
I have (own) sunglasses. – You own them, but you might not be wearing them.

So for “I often wear sunglasses,” često nosim sunčane naočale is the natural choice.

Why is sunčane naočale plural? In English we also say “sunglasses” but what about just “a pair of sunglasses”?

In Croatian, naočale (glasses) is always plural. There is no singular form used in practice.

naočale – glasses
sunčane naočale – sunglasses

Even if you mean one pair, you still use the plural:

Nove sunčane naočale – a new pair of sunglasses
Gdje su moje naočale? – Where are my glasses?

So sunčane naočale is grammatically plural, just like English sunglasses, and you use it even when you’re talking about one pair.

What gender and case are sunčane naočale, and why does sunčane end in -e?

Breakdown:

naočale is a feminine plural noun (NOM/ACC plural: naočale)
In the sentence, it is the direct object of nosim, so it’s in the accusative plural.

For feminine nouns, nominative plural and accusative plural usually look the same:

NOM pl: (te) sunčane naočale – subject
ACC pl: nosim sunčane naočale – object

The adjective sunčane must agree with naočale in:

gender: feminine
number: plural
case: accusative

That agreement gives you the form sunčane (feminine accusative plural), matching naočale.

Is kad the same as kada? Which one should I use?

Kad and kada mean the same thing: when.

Kad je sunce jako, nosim sunčane naočale.
Kada je sunce jako, nosim sunčane naočale.

Both are correct. Kad is just a shorter, more colloquial form; kada can sound a bit more formal or careful, but the difference is small.

In everyday speech, kad is very common. In writing, both appear often.

Why is the word order kad je sunce jako and not kad je jako sunce?

Kad je sunce jako is the normal, neutral word order:

sunce – the subject
je – verb “to be”
jako – predicate complement (an adverb here describing how strong/bright it is)

So it literally follows the pattern: when the sun is strong.

The version kad je jako sunce is not wrong, but it sounds less natural in this context. It tends to sound like special emphasis on jako sunce (as if strong sun were a noun phrase), which is not what you usually want here.

For ordinary “when the sun is strong/bright,” you say:

kad je sunce jako

Does jako here mean “very” or “strong”? Could I use vrlo instead?

In this sentence, jako is best understood as strong / intense / very bright, with the idea of strong sunlight.

jako sunce / sunce je jako
– the sun is strong / intense

You can say:

kad je sunce vrlo jako – when the sun is very strong

On its own:

jako can mean strongly or, colloquially, very
vrlo is a more neutral, standard word for very

In descriptions of weather and sunlight, jako is very natural.

Can I change the order of ljeti and često? For example, Često ljeti nosim sunčane naočale?

Yes, you can move ljeti and često around. All of these are acceptable, with only slight differences in emphasis:

Ljeti često nosim sunčane naočale.
In summer, I often wear sunglasses. (focus on the time “in summer”)
Često ljeti nosim sunčane naočale.
I often, in summer, wear sunglasses. (slightly more focus on the frequency “often”)
Često nosim sunčane naočale ljeti.
Also possible; emphasis more at the start on often.

The original word order is very natural, but moving the adverbs within the clause is generally allowed.

Why is there no article before sunce? In English we say “the sun”.

Croatian does not have articles like the or a/an.

So:

sunce
can mean sun / the sun depending on context.

In kad je sunce jako, context makes it obvious we mean the sun (the one in the sky), so no article is needed and none is possible anyway. You simply say sunce.

What verb aspect is nositi, and how would I talk about just one specific occasion of wearing sunglasses?

Nositi is imperfective, used for:

habits and repeated actions
ongoing actions
general statements

So:

Ljeti često nosim sunčane naočale.
– In summer I often wear sunglasses (habit).

For one specific occasion (for example, “I will bring/wear sunglasses with me once”), Croatian might use a perfective verb like ponijeti (to take/bring with, to put on once):

Sutra ću ponijeti sunčane naočale.
Tomorrow I will bring/wear sunglasses. (one event)

For general, habitual wearing, nositi is exactly right.

How do you pronounce lj in ljeti, and is it different from English “l”?

The lj in ljeti is a single Croatian sound, a palatalized l, written as the digraph lj.

It is similar to the “lli” in English million or familiar, but a bit clearer and always pronounced that way.
It is not the same as a plain English l.

So ljeti is roughly like lyeti, with lye as in lye or the lli in million, followed by ti.