Na otiraču ispred vrata uvijek ostavljamo mokre cipele.

Because after na meaning on, Croatian uses the locative case when the location is static.

• otirač = doormat
• na otiraču = on the doormat

If there were movement onto the doormat, you would use the accusative:

• Stavljam cipele na otirač. = I am putting the shoes onto the doormat.

So here, since the shoes are being left there, na otiraču is the correct form.

Otiraču is the locative singular of otirač.

The base noun is:

• otirač = doormat

In the locative singular, many masculine nouns take endings like -u or -e, and here the form is:

• otirač → otiraču

So:

• na otiraču = on the doormat

This is just a standard case form you need to learn with the noun.

The preposition ispred means in front of and it requires the genitive case.

So:

• ispred
  • genitive

The noun here is vrata:

• vrata = door / the door

Its genitive form is also vrata, so you get:

• ispred vrata = in front of the door

Even though the form looks unchanged, it is still functioning as genitive after ispred.

Because vrata is one of those Croatian nouns that are normally used only in the plural form, even when referring to a single object.

So:

• vrata = door
• grammatically plural, but often singular in meaning

This is similar to how some English nouns behave unusually, though not in exactly the same way.

Because it is treated as plural grammatically, other words agreeing with it can also appear in plural forms in other sentences.

Ostavljamo is the 1st person plural present tense of ostavljati, meaning we leave or we are leaving.

Breakdown:

• ostavljati = to leave, to put down, to leave behind
• ostavljamo = we leave

The ending -mo is the usual marker for we in the present tense.

So:

• ostavljamo = we leave

In Croatian, the present tense is commonly used for habitual actions, just like in English.

So uvijek ostavljamo means:

• we always leave
• a repeated or habitual action

You do not need a special tense for this. The word uvijek already makes it clear that this is something that happens regularly.

Because cipele is in the accusative plural, and the adjective must agree with it.

• cipele = shoes
• mokre = wet

The verb ostavljamo takes a direct object: what do we leave?
Answer: mokre cipele

For feminine plural nouns like cipele, the adjective also takes the matching plural form:

• mokre cipele = wet shoes

So the adjective and noun match in:

• gender
• number
• case

Here it is accusative plural, because it is the direct object of ostavljamo.

However, for many feminine plural nouns, the nominative plural and accusative plural look the same.

So:

• nominative plural: cipele
• accusative plural: cipele

You tell the case from the sentence function, not just from the form.

Yes, Croatian word order is fairly flexible, and uvijek can often move.

The sentence:

• Na otiraču ispred vrata uvijek ostavljamo mokre cipele.

is completely natural.

You could also say:

• Uvijek ostavljamo mokre cipele na otiraču ispred vrata.
• Mokre cipele uvijek ostavljamo na otiraču ispred vrata.

The meaning stays basically the same, but the emphasis changes a little.

In your original sentence, starting with Na otiraču ispred vrata gives the location extra focus.

Croatian often puts the most relevant or contextual information first.

So starting with:

• Na otiraču ispred vrata = On the doormat in front of the door

sets the scene before telling you what happens there.

This is very natural in Croatian. English often prefers a more fixed order, but Croatian is freer because cases show the grammatical roles more clearly.

Sometimes yes, but the meaning is slightly different.

• ispred vrata = in front of the door
• pred vratima = in front of the door / before the door

In many everyday contexts they can be very similar. But ispred more literally emphasizes a position out in front of something. It is very common for physical location.

Also note the case difference:

• ispred
  • genitive → ispred vrata
• pred
  • instrumental → pred vratima

So both can work in many contexts, but they are not built the same way.

Because Croatian usually does not need an explicit subject pronoun when the verb ending already shows who is doing the action.

• ostavljamo already means we leave

So mi = we is unnecessary unless you want extra emphasis or contrast.

For example:

• Mi uvijek ostavljamo mokre cipele...
  = We always leave wet shoes...
  This might emphasize we, as opposed to someone else.

Yes. Ostavljati is a very natural verb here.

It can mean:

• to leave
• to leave behind
• to put and leave somewhere

In this sentence it suggests placing the shoes somewhere and letting them stay there.

So ostavljamo mokre cipele na otiraču means something like:

• we leave the wet shoes on the doormat
• we keep putting the wet shoes there

It fits very well with a habitual action.

Because the sentence describes a repeated, habitual action, not a single completed event.

• ostavljati = imperfective
• habitual / ongoing / repeated action

With uvijek (always), the imperfective is the natural choice.

A perfective verb would sound more like a single completed act or a specific result, which does not fit as well here.

A rough pronunciation guide is:

• Na otiraču ispred vrata uvijek ostavljamo mokre cipele
• nah oh-tee-RAH-choo ees-PRED VRAH-tah OO-vyek oh-STAHV-lya-moh MOH-kreh TSYEH-peh-leh

A few helpful points:

• č sounds like ch in church
• c sounds like ts
• j sounds like English y
• ije in uvijek is pronounced smoothly, roughly oo-vyek

This is only approximate, but it is enough to get started.

Here are the main dictionary forms:

• otirač = doormat
• ispred = in front of
• vrata = door
• uvijek = always
• ostavljati = to leave
• mokar = wet
• cipela = shoe

And the forms used in the sentence are:

• otiraču = locative singular of otirač
• vrata = genitive after ispred here
• ostavljamo = we leave
• mokre = plural form of mokar
• cipele = plural of cipela here functioning as the object