Lähtöaulassa on jo paljon ihmisiä, vaikka kuulutusta ei ole vielä tullut.

It is a compound word plus a case ending:

• lähtö = departure
• aula = hall, lobby
• lähtöaula = departure hall
• -ssa = the inessive case, meaning in

So lähtöaulassa literally means in the departure hall.

Finnish makes compounds very freely, so long words like this are very common.

Because this is an existential sentence: it tells us that something exists or is present somewhere.

Structure:

• Lähtöaulassa = in the departure hall
• on = is
• paljon ihmisiä = a lot of people

In Finnish, existential sentences often use singular on, even when the thing being talked about is plural.

So Finnish says something closer to:

• In the departure hall is a lot of people

But natural English becomes:

• There are already a lot of people in the departure hall

This singular verb in Finnish is very normal in this kind of sentence.

Because after words of quantity such as paljon = a lot of, the following noun usually goes into the partitive.

So:

• paljon = a lot of
• ihmisiä = people, in the partitive plural

The basic word is ihminen = person.
Its partitive plural is ihmisiä.

This structure is extremely common:

• paljon vettä = a lot of water
• paljon autoja = a lot of cars
• paljon ihmisiä = a lot of people

So the partitive here is required by the quantity expression.

Jo means already.

It suggests that the situation happens earlier than expected or sooner than the speaker might have assumed.

So:

• Lähtöaulassa on jo paljon ihmisiä
  = There are already a lot of people in the departure hall

The feeling is that the departure hall is crowded even at this point.

Vaikka means although, even though, or sometimes though.

It introduces a contrast:

• Lähtöaulassa on jo paljon ihmisiä
  vaikka
• kuulutusta ei ole vielä tullut

So the idea is:

• there are already many people there,
• even though the announcement has not come yet.

It is a very common conjunction for showing contrast between two facts.

Because in this clause, Finnish treats the announcement as something that has not yet appeared / happened, and the clause is also negative.

• kuulutus = announcement
• kuulutusta = partitive singular

The full clause is:

• kuulutusta ei ole vielä tullut

Literally, this is close to:

• an announcement has not yet come
• or there has not yet been an announcement

A key point: tulla = to come is not taking a direct object here, so kuulutusta is not an object in the usual sense. It is part of an existential-like construction, and the partitive is natural in negative sentences of this type.

Compare:

• Täällä ei ole kahvia. = There is no coffee here.
• Bussia ei ole vielä tullut. = The bus hasn’t come yet / There hasn’t been a bus yet.

It is the negative present perfect.

Parts:

• ei = negative verb, 3rd person singular
• ole = form of olla used in the perfect
• tullut = past participle of tulla = to come
• vielä = yet, still

So:

• ei ole tullut = has not come
• ei ole vielä tullut = has not come yet

This is a very common Finnish perfect structure.

They do point in opposite time directions, but that is exactly why they work well together here.

• jo = already
• vielä = yet

They refer to different parts of the situation:

• already many people are in the departure hall
• the announcement has not yet come

So the sentence creates a contrast:

• it feels a bit early for there to be so many people,
• because the announcement still hasn’t happened.

That makes the whole sentence sound very natural.

Finnish word order is fairly flexible, but changing it changes the focus or emphasis.

This version is natural and neutral:

• Lähtöaulassa on jo paljon ihmisiä, vaikka kuulutusta ei ole vielä tullut.

You could also say:

• Vaikka kuulutusta ei ole vielä tullut, lähtöaulassa on jo paljon ihmisiä.

That puts the although-clause first and makes the contrast more prominent from the start.

So yes, the order can change, but the current sentence is very normal.

Finnish has no articles like English a/an/the.

That means words like lähtöaulassa, ihmisiä, and kuulutusta do not themselves show whether something is a, an, or the. Context tells you that.

For example:

• lähtöaulassa can mean in a departure hall or in the departure hall
• kuulutusta can correspond to an announcement, any announcement, or sometimes the announcement, depending on context

English has to choose an article, but Finnish usually does not.