Laura odottaa minua lähtöaulassa, koska hänen lentonsa lähtee samasta terminaalista.

Because odottaa normally takes its object in the partitive case.

• minä = I (basic form)
• minut = me in an object form used in some other contexts
• minua = me in the partitive

So Laura odottaa minua is the normal Finnish pattern for Laura is waiting for me. With odottaa, learners should usually just remember: odottaa + partitive.

Lähtöaulassa is the word lähtöaula plus the ending -ssa.

• lähtöaula = departure hall
• -ssa / -ssä = in (the inessive case)

So lähtöaulassa means in the departure hall.

Finnish often expresses location with case endings instead of separate prepositions like in, from, or to.

Yes. They come from the same root.

• lähteä = to leave / to depart
• lähtee = leaves / departs (3rd person singular of lähteä)
• lähtö = departure (a noun formed from the same root)

So:

• lähtöaula = literally departure hall
• lentonsa lähtee = her flight departs

This is a very common pattern in Finnish: a verb and a related noun can look similar.

Yes, it can.

Finnish koska has two common uses:

• because as a conjunction
• when? as a question word

In this sentence, it is clearly the conjunction because:

..., koska hänen lentonsa lähtee samasta terminaalista.

That means ..., because her flight leaves from the same terminal.

If it were a question word, it would usually appear in a question such as Koska lento lähtee? = When does the flight leave?

Because Finnish normally separates a main clause and a subordinate clause with a comma.

Here:

• main clause: Laura odottaa minua lähtöaulassa
• subordinate clause: koska hänen lentonsa lähtee samasta terminaalista

So the comma is standard Finnish punctuation. This is one place where Finnish often uses a comma more regularly than English does.

This is how 3rd person possession is often marked in standard Finnish.

• hänen = his / her
• lento = flight
• lentonsa = his/her flight with the possessive suffix -nsa / -nsä

So hänen lentonsa literally contains possession twice, but that is normal Finnish.

You can think of it as:

• hänen shows the possessor
• -nsa also marks that the noun belongs to that 3rd person possessor

In modern Finnish, especially in careful written language, this is very common and natural.

It can mean either one.

Finnish does not normally mark gender in the 3rd person singular the way English does. The pronoun hän means he or she, and hänen means his or her.

In this sentence, we know it refers to Laura, so English uses her: hänen lentonsa = her flight

Because the verb lähteä often uses the case that means from a place.

• terminaali = terminal
• terminaalista = from the terminal (the elative case)
• samasta = from the same, matching the same case

So samasta terminaalista means from the same terminal.

This contrasts with lähtöaulassa, which uses a case meaning in:

• lähtöaulassa = in the departure hall
• terminaalista = from the terminal

Finnish is very precise about location:

• -ssa / -ssä = in
• -sta / -stä = from inside / out of

Because adjectives in Finnish usually agree with the noun they describe in case and number.

The basic form is:

• sama = same

But here the noun is terminaalista, which is in the elative case, so the adjective must also be in the elative:

• sama terminaali = the same terminal
• samasta terminaalista = from the same terminal

This kind of agreement is very important in Finnish.

Because Finnish has no articles.

So Finnish does not have separate words corresponding directly to English a/an and the. Instead, definiteness is understood from context.

For example:

• lentonsa can mean her flight
• terminaalista can mean from the terminal or from a terminal, depending on context

In this sentence, the context makes the same terminal the natural English translation.

Not completely. Finnish word order is more flexible than English word order because the case endings show what each word is doing.

The sentence as written is a very natural, neutral order:

Laura odottaa minua lähtöaulassa, koska hänen lentonsa lähtee samasta terminaalista.

Very roughly:

• Laura = subject
• odottaa = verb
• minua = object
• lähtöaulassa = place
• koska... = reason clause

Some parts could be moved for emphasis, but the original version is the most straightforward. A learner should treat this as a standard, normal sentence pattern.