Teen lähtöselvityksen vasta lentokentällä, koska netti ei toimi kotona.

Finnish often leaves out the subject pronoun when it is clear from the verb ending.

• teen = I do / I am doing
• the ending -n already shows the subject is I

So Teen lähtöselvityksen... is a natural way to say I check in / I’m doing the check-in...

You could say Minä teen lähtöselvityksen, but that would usually add emphasis, as if you wanted to stress I specifically.

Lähtöselvitys means check-in.

It is a compound noun:

• lähtö = departure
• selvitys = clarification, processing, clearance

So the literal idea is something like departure processing/clearance, which in travel context means check-in.

Finnish uses compound words very freely, so long words like this are very common.

In the sentence, the form is lähtöselvityksen, not the basic dictionary form lähtöselvitys.

Here lähtöselvityksen is the object of teen.

With many verbs, Finnish marks a complete, whole object with -n in sentences like this. This is often called the total object.

So:

• teen lähtöselvityksen = I do the check-in / I complete the check-in

The -n shows that the action is seen as a whole completed action, not just part of it.

Compare the basic form:

• lähtöselvitys = check-in

But in this sentence:

• teen lähtöselvityksen = I do the check-in

Yes. Both are possible.

• Teen lähtöselvityksen = literally I do the check-in
• Lähtöselvittäydyn = I check in

The first is very transparent for learners and very common in everyday Finnish. The second is a single verb built from the same idea.

In practice, both can be used, but teen lähtöselvityksen is often easier to understand at first because it is more literal.

Here vasta means something like:

• only
• not until

So:

• Teen lähtöselvityksen vasta lentokentällä
  = I’ll only do the check-in at the airport = I won’t do it until I’m at the airport

This word often gives the idea that something happens later than expected or only at that point.

Examples:

• Tulen vasta huomenna. = I’m only coming tomorrow / I won’t come until tomorrow.
• Söin vasta nyt. = I only ate now / I didn’t eat until now.

Because Finnish uses case endings instead of prepositions like at, in, or on.

• lentokenttä = airport
• lentokentällä = at the airport

The ending -lla / -llä is the adessive case, which often means on, at, or by.

So:

• vasta lentokentällä = only at the airport

Kotona is the normal word for at home.

Even though koti means home, the location expression is usually:

• kotona = at home

This is a very common fixed form that learners simply have to get used to.

You may also see:

• kotiin = to home / homeward
• kotoa = from home

So in the sentence:

• netti ei toimi kotona = the internet doesn’t work at home

Kodissa would mean something more like in the home/house, and it is not the normal everyday way to say at home.

Finnish negation uses a special negative verb.

So instead of one word meaning does not work, Finnish splits it into two parts:

• ei = negative verb for he/she/it and singular non-human subjects in this kind of sentence
• toimi = the main verb in a special form used after negation

So:

• netti toimii = the internet works
• netti ei toimi = the internet does not work

This pattern is very important in Finnish:

• en tiedä = I don’t know
• et tiedä = you don’t know
• ei tiedä = he/she/it doesn’t know

The negative verb changes for person, but the main verb stays in a special stem-like form.

Because netti is the subject, and the normal word order is:

• subject + negative verb + main verb

So:

• netti ei toimi = the internet doesn’t work

Finnish word order is flexible, but this is the neutral, standard order.

If you moved things around, you would usually create emphasis or a special contrast.

Finnish often uses the present tense for future meaning when the context makes it clear.

So:

• Teen lähtöselvityksen vasta lentokentällä

can mean:

• I’m doing the check-in only at the airport
• or more naturally in English, I’ll check in only at the airport

The sentence is about a planned future action, but Finnish does not need a separate future tense here.

This is very common in Finnish.

Because koska introduces a subordinate clause:

• main clause: Teen lähtöselvityksen vasta lentokentällä
• subordinate clause: koska netti ei toimi kotona

In Finnish, a subordinate clause is normally separated by a comma.

So the comma here is standard punctuation.

Usually, yes. In sentences like this, koska means because.

• ..., koska netti ei toimi kotona. = ..., because the internet doesn’t work at home.

However, koska can also mean when in some contexts, especially in more formal or older-style usage. For most learners, though, the most important meaning is because.

If you want when in everyday Finnish, you will often see kun instead.

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

So Finnish simply says:

• lentokentällä = at the airport / at an airport
• netti = the internet / internet
• lähtöselvityksen = the check-in / a check-in

The exact meaning depends on context.

In this sentence, English naturally uses the in places, but Finnish does not need any article at all.