Kad teško dišem, koristim inhalator i sjednem kraj otvorenog prozora.

Kad means when.

In this sentence, Kad teško dišem means When I breathe with difficulty / When I’m having trouble breathing.

Kad and kada usually mean the same thing. The difference is mostly style:

• kad = more common in everyday speech
• kada = a bit more formal or careful

So both are possible:

• Kad teško dišem...
• Kada teško dišem...

Both are correct.

Dišem is the 1st person singular present tense of the verb disati = to breathe.

So:

• ja dišem = I breathe
• ti dišeš = you breathe
• on/ona diše = he/she breathes

Croatian usually does not need the subject pronoun ja because the verb ending already shows who the subject is. That is why the sentence says dišem, not ja dišem.

Here teško means with difficulty or hard in the sense of not easily.

So teško dišem means:

• I breathe with difficulty
• I’m breathing heavily / with difficulty
• I’m having trouble breathing

This is an adverb, describing how you breathe.

Be careful: teško can have several related meanings depending on context, such as:

• hard / difficult
• heavily
• with difficulty

In this sentence, it modifies the verb dišem.

Koristim is the 1st person singular present tense of koristiti = to use.

So:

• koristim inhalator = I use an inhaler

This is straightforward present tense. It works well here because the sentence describes a usual reaction or repeated action: When this happens, I use an inhaler...

Also, inhalator is in the accusative singular, but for this masculine noun the accusative form looks the same as the nominative:

• nominative: inhalator
• accusative: inhalator

That is normal for many masculine inanimate nouns in Croatian.

Croatian has no articles like English a, an, the.

So inhalator can mean:

• an inhaler
• the inhaler

Which one is meant depends on context.

In this sentence, English naturally says an inhaler, but Croatian just says inhalator.

This is a very important difference.

• sjediti → sjedim = to sit, I am sitting
• sjesti → sjednem = to sit down, I sit down

So:

• sjedim kraj prozora = I am sitting by the window
• sjednem kraj prozora = I sit down by the window

In your sentence, the meaning is I use an inhaler and then sit down by an open window, so sjednem is the right choice because it expresses the action of becoming seated.

Croatian often uses the present tense to describe:

• habitual actions
• repeated actions
• what someone regularly does in a certain situation

So Kad teško dišem, koristim inhalator i sjednem... means something like:

• When I have trouble breathing, I use an inhaler and sit down...
• Whenever I have trouble breathing, I use an inhaler and sit down...

Even though sjednem comes from a perfective verb (sjesti), this kind of use is normal in sentences describing what happens whenever a situation occurs.

The idea is not a single event in the future, but a regular sequence:

1. breathing becomes difficult
2. I use the inhaler
3. I sit down by the window

Yes, but it changes the meaning.

• sjednem kraj otvorenog prozora = I sit down by an open window
• sjedim kraj otvorenog prozora = I sit by an open window / I am sitting by an open window

So:

• sjednem focuses on the action of taking a seat
• sjedim focuses on the state of already being seated

In your sentence, sjednem sounds more natural if you want to describe what you do in response.

Kraj here means by, next to, or beside.

So:

• kraj otvorenog prozora = by an open window

It is a common preposition, though learners also often meet:

• pored = next to / beside
• uz = by / along / next to in some contexts

In this sentence, kraj is completely natural.

Because the preposition kraj requires the genitive case.

The noun is prozor = window.

After kraj, it changes to genitive singular:

• nominative: prozor
• genitive: prozora

The adjective has to agree with the noun in case, gender, and number:

• nominative masculine singular: otvoren prozor
• genitive masculine singular: otvorenog prozora

So:

• kraj otvorenog prozora = by an open window

Because it is a masculine singular genitive adjective form.

The noun prozor is:

• masculine
• singular
• in the genitive case after kraj

So the adjective must match it:

• otvoren = masculine singular nominative
• otvorenog = masculine singular genitive

This agreement is a core feature of Croatian grammar: adjectives match the nouns they describe.

More or less, yes.

A very literal breakdown would be:

• kraj = beside / by
• otvorenog = open (genitive form)
• prozora = window (genitive form)

So literally: by an open window.

English and Croatian do not always match word for word, but the structure is normal Croatian.

Because Kad teško dišem is a subordinate clause placed before the main clause.

Croatian normally puts a comma after an introductory clause like this:

• Kad teško dišem, koristim inhalator...

This is similar to English:

• When I have trouble breathing, I use an inhaler...

So the comma is standard and expected.

Because Croatian verbs already show the subject clearly.

• dišem = I breathe
• koristim = I use
• sjednem = I sit down

Adding ja is possible, but it usually adds emphasis or contrast:

• Ja koristim inhalator, a on ne.
  I use an inhaler, but he doesn’t.

Without emphasis, Croatian usually leaves the pronoun out.

It has two main parts:

1. Kad teško dišem
   = When I breathe with difficulty / When I have trouble breathing

2. koristim inhalator i sjednem kraj otvorenog prozora
   = I use an inhaler and sit down by an open window

So the full structure is:

• When X happens, I do Y and Z.

This is a very common Croatian pattern:

• Kad + clause, main clause

For example:

• Kad sam umoran, pijem čaj.
  When I’m tired, I drink tea.

A natural English translation could be:

• When I have trouble breathing, I use an inhaler and sit down by an open window.

Possible alternatives:

• When I’m having difficulty breathing, I use an inhaler and sit down by an open window.
• When I can’t breathe easily, I use an inhaler and sit by an open window.

The Croatian itself is natural and clear.

Yes. In this kind of sentence, kad often has the sense of whenever.

So the sentence can be understood as:

• When/Whenever I have trouble breathing, I use an inhaler and sit down by an open window.

That is because the sentence describes a habitual response, not just one specific moment.

Not completely. Croatian word order is more flexible than English, though some orders sound more natural than others.

The original sentence is very natural:

• Kad teško dišem, koristim inhalator i sjednem kraj otvorenog prozora.

You could also hear variations such as:

• Kad teško dišem, sjednem kraj otvorenog prozora i koristim inhalator.

But that changes the emphasis and possibly the order of actions.

So the original order suggests a natural sequence:

1. use the inhaler
2. sit down by the open window

Roughly:

• dišem ≈ DEE-shem
• sjednem ≈ SYED-nem or SJED-nem

A few helpful points:

• š sounds like English sh
• j sounds like English y
• dj/sj-type clusters can feel unusual for English speakers, so sjednem may take practice

Also:

• prozora ≈ pro-ZO-ra
• otvorenog ≈ ot-VO-re-nog

Croatian spelling is quite regular, so pronunciation is usually more predictable than in English.