Minä valitsen käytäväpaikan, mutta siskoni haluaa aina ikkunapaikan.

Yes. Finnish often leaves out subject pronouns because the verb ending already shows the person.

So valitsen käytäväpaikan already means I choose an aisle seat.

Adding minä gives a little extra emphasis or contrast, which fits well here because the sentence then contrasts I with my sister.

Valitsen is the 1st person singular present tense of valita, meaning to choose.

A simple breakdown is:

• valita = to choose
• valitsen = I choose

Finnish verbs change form to show who is doing the action, so the -n ending tells you it is I.

Because these words are the objects of the verbs, and here they refer to one whole seat each.

In a normal positive sentence like this, Finnish often uses the total object for a single complete thing. In this pattern, the singular total object usually looks like -n.

So:

• käytäväpaikka → käytäväpaikan
• ikkunapaikka → ikkunapaikan

Those are partitive forms, and they are not the neutral choice here.

This sentence is talking about choosing or wanting a complete seat, not just some undefined amount of something. That is why Finnish uses the total object instead of the partitive.

So:

• valitsen käytäväpaikan = I choose an aisle seat
• haluaa ikkunapaikan = wants a window seat

That sounds natural for one specific seat as a whole.

Yes. Finnish uses compound words very often.

These are made like this:

• käytävä = aisle
• ikkuna = window
• paikka = place, spot, seat

So:

• käytäväpaikka = aisle seat
• ikkunapaikka = window seat

English often writes similar ideas as two words, but Finnish usually combines them into one.

Yes, it can mean both.

In buildings, käytävä often means corridor/hallway. In travel or seating contexts, it also means aisle.

So käytäväpaikka is the normal way to say aisle seat.

Siskoni means my sister.

It breaks down like this:

• sisko = sister
• -ni = my

So siskoni literally means sister-my.

You can also say minun siskoni, and that is correct too. But Finnish often uses the possessive suffix -ni without the separate word minun, unless the speaker wants extra emphasis.

Haluaa is the 3rd person singular present tense of haluta, meaning to want.

Compare:

• minä haluan = I want
• sinä haluat = you want
• hän haluaa = he/she wants

Since siskoni is the subject of the second clause, the verb must be the 3rd person singular form: haluaa.

Aina means always, and here it is an adverb.

The neutral word order is:

subject + verb + adverb + object

So:

• siskoni haluaa aina ikkunapaikan

is a very natural order.

Finnish word order is flexible, but moving aina to another place would usually change the emphasis.

Because mutta means but and joins two independent clauses here.

Each clause has its own verb:

• Minä valitsen käytäväpaikan
• siskoni haluaa aina ikkunapaikan

In Finnish, a comma is normally used before mutta in this kind of sentence.

Because the two verbs express slightly different ideas:

• valita = to choose
• haluta = to want

So the sentence is not saying exactly the same thing twice. It shows a contrast between:

• what I choose
• what my sister always wants

If you said siskoni valitsee aina ikkunapaikan, that would mean my sister always chooses a window seat, which is a bit more about the actual action of selecting it than about her preference.

Finnish does not have articles like a, an, or the.

That means words like käytäväpaikan and ikkunapaikan do not contain a separate article. English has to add one when translating.

Depending on context, they could mean:

• an aisle seat / a window seat
• the aisle seat / the window seat

In this sentence, the most natural English translation is usually an aisle seat and a window seat.