Mrav puže po deki, a mali pauk stoji na rubu stola.

Croatian does not have articles.

So:

• mrav can mean an ant or the ant
• mali pauk can mean a small spider or the small spider

The exact meaning depends on context. If a speaker wants to be more specific, they can use words like:

• jedan = a certain / one
• taj = that / that particular

But in a normal sentence like this, no article is needed.

Because po here requires the locative case.

The basic form is:

• deka = blanket

After po in the sense of movement over/across/on a surface, it becomes:

• po deki

So:

• deka → nominative singular
• deki → locative singular

This is very common in Croatian: the noun changes form depending on its role and the preposition used with it.

Because na with a static location uses the locative case.

Here the spider is standing somewhere, not moving onto the edge. So Croatian uses:

• na rubu = on the edge

Compare:

• na rubu = on the edge / at the edge (location)
• na rub = onto the edge (movement toward it)

So in this sentence, rubu is locative because it tells you where the spider is.

Because stola is the genitive singular of stol (table).

The phrase rub stola literally works like edge of the table:

• rub = edge
• stola = of the table

So in na rubu stola:

• rubu = locative, after na
• stola = genitive, because it depends on rub

This kind of noun + genitive structure is very common in Croatian:

• vrata kuće = the door of the house
• kraj puta = the end of the road
• rub stola = the edge of the table

This is a very useful distinction.

• na deki usually focuses on location: on the blanket
• po deki often suggests movement over the surface: along / across / over the blanket

Since the ant is crawling, po deki sounds natural because it emphasizes movement across the blanket.

So:

• Mrav je na deki = The ant is on the blanket
• Mrav puže po deki = The ant is crawling over/across the blanket

A often connects two clauses with a slight sense of contrast or switch of focus.

Here it is something like:

• The ant is crawling on the blanket, while the small spider is standing on the edge of the table.

It can sometimes be translated as:

• and
• while
• whereas
• but

depending on context.

In this sentence, a is not a strong but. It is more like while/and meanwhile: one creature is doing one thing, and the other is doing another.

The infinitive is puzati = to crawl.

In the present tense, it conjugates like this:

• ja pužem = I crawl / am crawling
• ti pužeš = you crawl
• on/ona/ono puže = he/she/it crawls

So:

• mrav puže = the ant crawls / is crawling

The z changes to ž in the present tense stem. That kind of sound change is normal in Croatian verb conjugation.

Because the adjective must agree with the noun.

Pauk (spider) is:

• masculine
• singular
• nominative here, because it is the subject

So the adjective must also be:

• masculine singular nominative → mali

Compare:

• mali pauk = small spider (masculine)
• mala mačka = small cat (feminine)
• malo dijete = small child (neuter)

This agreement of adjective + noun is one of the basic patterns in Croatian.

Croatian often uses more specific position verbs where English might simply use is.

• stajati / stoji = to stand / is standing
• ležati / leži = to lie / is lying
• sjediti / sjedi = to sit / is sitting

So mali pauk stoji na rubu stola literally means the small spider stands on the edge of the table, but in natural English that may simply be translated as the small spider is on the edge of the table.

Croatian likes to show the physical position more clearly than English often does.

Yes.

Croatian present tense often covers both:

• simple present: crawls
• present continuous: is crawling

So:

• Mrav puže can mean The ant crawls or The ant is crawling
• Pauk stoji can mean The spider stands or The spider is standing

The context tells you whether it is a general fact or something happening right now. In a sentence like this, it most naturally sounds like something happening right now.

Not completely. Croatian word order is fairly flexible because cases show the grammatical roles.

The neutral order here is:

• Mrav puže po deki, a mali pauk stoji na rubu stola.

But other orders are possible for emphasis, for example:

• Po deki puže mrav...
• Na rubu stola stoji mali pauk...

These alternatives can sound more poetic, marked, or focused on the location. For a learner, the original order is the safest and most natural neutral choice.

A rough guide:

• mrav ≈ mrahv
• puže ≈ POO-zheh
• deki ≈ DEH-kee
• pauk ≈ PAH-ook
• rubu ≈ ROO-boo
• stola ≈ STOH-lah

A few useful sound notes:

• ž sounds like the s in measure
• j in Croatian sounds like English y
• vowels are usually clear and short, not reduced like many English vowels

So puže is not pooze with an English z sound; it is POO-zheh with ž.