Pokret traje kratko.

Pokret is nominative singular. It is the subject of the sentence, the thing that traje.

A native English speaker might expect something like the movement, but Croatian just uses the bare noun:

• pokret = movement / motion / gesture, depending on context

It is a masculine noun.

Croatian normally has no articles. So pokret can mean:

• a movement
• the movement

The exact meaning depends on context. This is very normal in Croatian.

Traje is the 3rd person singular present tense of the verb trajati (to last, to continue, to take some time).

It is 3rd person singular because the subject pokret is singular:

• pokret traje = the movement lasts

Some related forms:

• ja trajem = I last
• ti traješ = you last
• on/ona/ono traje = he/she/it lasts
• oni traju = they last

Because kratko is an adverb, and it modifies the verb traje.

So the structure is:

• traje = lasts
• kratko = briefly / for a short time

By contrast, kratak is an adjective, used to describe a noun:

• kratak pokret = a short movement

In your sentence, we are not directly describing the noun pokret with an adjective. We are describing how long it lasts, so Croatian uses the adverb:

• Pokret traje kratko.

Yes, you could, and it is grammatical. But it is not exactly the same structure.

• Pokret traje kratko. = The movement lasts a short time.
• Pokret je kratak. = The movement is short.

The meaning is very similar, but the grammar is different:

• traje kratko = verb + adverb
• je kratak = to be
  • adjective

Both are natural. The version with traje focuses more directly on duration.

In this sentence, for a short time is usually the clearest way to think about it.

So:

• Pokret traje kratko. = The movement lasts for a short time.

English often uses briefly, and that is close in meaning, but Croatian kratko here is very literally about short duration.

Yes. Croatian word order is fairly flexible.

Possible versions include:

• Pokret traje kratko.
• Pokret kratko traje.

Both are grammatical. The most neutral version is usually:

• Pokret traje kratko.

Changing the order can slightly shift emphasis:

• Pokret kratko traje can put a bit more focus on kratko

But for a learner, the original order is a good default.

Trajati is imperfective.

That makes sense, because it describes an ongoing state or duration:

• something lasts

Croatian often uses imperfective verbs for actions or states seen as ongoing, repeated, or extended in time.

Examples:

• Sastanak traje dugo. = The meeting lasts a long time.
• Film traje dva sata. = The film lasts two hours.

If you want past time, you still use the same verb in the past:

• Pokret je trajao kratko. = The movement lasted a short time.

Yes. Pokret can have several related meanings depending on context, such as:

• a physical movement
• a motion
• a gesture
• a movement in the political or artistic sense

So without context, the sentence could refer to:

• a body movement
• a mechanical motion
• some other kind of movement

The grammar stays the same either way.

In the past, you would usually say:

• Pokret je trajao kratko.

Here:

• je = auxiliary to be
• trajao = past participle of trajati, masculine singular to agree with pokret

So:

• present: Pokret traje kratko.
• past: Pokret je trajao kratko.

A simple learner-friendly pronunciation guide is:

• Pokret ≈ PO-kret
• traje ≈ TRA-ye
• kratko ≈ KRAT-ko

So the whole sentence sounds roughly like:

• PO-kret TRA-ye KRAT-ko

The j in Croatian is pronounced like English y in yes, so traje is not trayj, but more like TRA-ye.