Learn Hardcore Croatian: Na vratima pozdravljamo goste.

So na vratima pozdravljamo goste is understood as “We greet the guests at the door.” Croatian uses na + locative here to express the place where something is happening.

Why is it na vratima and not na vrata?

Because of the difference between location and direction:

na
- locative = location (where something is):
- na vratima = at/on the door(s) → static place
na
- accusative = direction (to where something is going):
- na vrata = onto/into the door/doorway → movement towards

In your sentence, the action is happening at a fixed place (we are already at the door), so Croatian uses locative: na vratima.

What case is vratima, and what is the base form of this noun?

Vratima is locative plural (and also dative plural form) of the noun vrata.

Details:

Dictionary form (nominative): vrata
Gender: neuter, always plural (pluralia tantum)
Meaning: “door” (as an object/opening), but grammatically plural

The locative plural ending -ima gives you vratima:

nominative plural: vrata
locative plural: (na) vratima → at the door

Why is “door” plural in Croatian (vrata) but singular in English?

Croatian treats vrata (“door”) as a plural-only noun:

You say:
- Vrata su otvorena. = “The door is open.”
  (Literally: Doors are open.)

English sees “door” as singular, but Croatian thinks of it as a two-wing or multi-part object and uses the plural form vrata by default. This is just a lexical difference you have to memorize: vrata always behaves like a plural noun.

What form is pozdravljamo, and what is the infinitive of this verb?

Pozdravljamo is:

present tense
1st person plural (“we”)
of the verb pozdravljati (to greet)
imperfective aspect

So:

infinitive: pozdravljati = “to be greeting / to greet (habitually, repeatedly)”
mi pozdravljamo = “we greet / we are greeting”

Conjugation (present, for reference):

ja pozdravljam
ti pozdravljaš
on/ona/ono pozdravlja
mi pozdravljamo
vi pozdravljate
oni/one/ona pozdravljaju

Why is there no mi (“we”) in the sentence? Could I say Mi na vratima pozdravljamo goste?

Croatian normally drops subject pronouns when the verb ending already shows the subject.

Pozdravljamo already tells you it’s “we” (1st person plural).
So mi is optional and usually omitted unless you want to emphasize “we”.

Both are grammatical:

Na vratima pozdravljamo goste. = neutral, normal
Mi na vratima pozdravljamo goste. = emphasizes we (e.g. not someone else)

What case is goste, and why not gosti?

Goste is accusative plural of gost (“guest”).

nominative singular: gost
nominative plural (subject): gosti
accusative plural (object): goste

In the sentence:

pozdravljamo koga? (whom do we greet?) → goste
Since gosti/goste are the direct object, they must be in the accusative case, so we use goste, not gosti.

Can I change the word order, for example to Pozdravljamo goste na vratima? Does it change the meaning?

Yes, you can change the word order:

Na vratima pozdravljamo goste.
Pozdravljamo goste na vratima.

Both are grammatically correct and mean essentially the same thing.

The difference is mostly in emphasis / information structure:

Na vratima pozdravljamo goste.
→ Slight emphasis on where it happens (“At the door we greet the guests.”).
Pozdravljamo goste na vratima.
→ Slightly more neutral; you first say what you do and to whom, then add where.

In normal conversation, both versions are fine and natural.

How does na vratima differ from kod vrata or pred vratima?

All three can relate to the area around a door, but with nuances:

na vratima
Literally “on/at the door”; often means at the threshold / at the doorway.
Used for someone standing right in the door area, ringing, entering, greeting, etc.
kod vrata
Literally “by/near the door”; focuses more on vicinity, not necessarily in the doorway.
pred vratima
Literally “in front of the door(s)”; emphasizes position in front of the door, usually outside.

In your sentence:

Na vratima pozdravljamo goste. → we greet them right at the door (as they come/enter).

Is there a perfective version of pozdravljamo, and how would the meaning change?

Yes. The usual aspect pair is:

pozdravljati (imperfective) – ongoing, habitual, repeated
pozdraviti (perfective) – a single, completed act

So:

pozdravljamo (from pozdravljati) = we greet / we are greeting (process or habit)
pozdravimo (from pozdraviti, 1st person plural present) is usually used as a future-like or one-time action, often in suggestions:
- Hajdemo, pozdravimo goste. = “Come on, let’s greet the guests (once).”

In Na vratima pozdravljamo goste, the imperfective makes sense because you’re describing what you (typically) do or what is happening, rather than a single completed act.

Could na vratima ever be understood as literally “on the surface of the door”?

Yes, in some contexts it can be taken literally:

Na vratima piše “GURATI”.
= “On the door it says ‘PUSH’.”
Na vratima je naljepnica.
= “There is a sticker on the door.”

In your sentence, the verb pozdravljamo (we greet) makes a literal “on the surface” reading unlikely, so native speakers automatically interpret na vratima as “at the door (area)” rather than “on the door panel.”

Is pozdravljamo formal or informal? Could I use this sentence in a polite context?

Pozdravljamo itself is neutral—neither particularly formal nor informal. The whole sentence:

Na vratima pozdravljamo goste.

is perfectly fine in:

everyday conversation,
describing your family’s or staff’s routine,
even in relatively polite or semi-formal speech.

For very formal writing (e.g. hotel brochure) you might slightly rephrase, but this sentence is still correct and acceptable in most contexts.