Learn Hardcore Turkish: Bu akşam sinema için iki kişilik yer ayırtıyorum. - I am reserving two seats for the cinema this evening.

Because ayırmak means “to separate/set aside (yourself),” while ayırtmak is the causative “to have something set aside,” i.e., “to reserve.” When you book with a cinema/restaurant, you cause them to set the place aside for you, so yer ayırtmak is the natural verb for “to reserve a seat/place.”

How is ayırtıyorum built morphologically?

It’s ayırt- + (I)yor + -um:

verb stem: ayırt- (“reserve”)
present continuous: -ıyor (because the last vowel in the stem is ı)
1st person singular: -um Altogether: ayırtıyorum. Note the past tense looks like it has a double t: ayırttım = ayırt- + -tı + -m.

Why is there no -i accusative on yer?

In Turkish, an indefinite direct object doesn’t take the accusative. iki kişilik yer ayırtıyorum = “I’m reserving a two-person place (some place).” If you mean a specific, known seat, you’d use the accusative: iki kişilik yeri ayırtıyorum (“I’m reserving the two-person seat”).

What exactly does iki kişilik mean, and why not iki kişi?

The suffix -lik here forms an adjective meaning “with a capacity of … / for ….” So iki kişilik yer = “a place for two people/a two-person place.”

Use -lik with things like oda, masa, yer, oda: iki kişilik oda/masa/yer.
If you’re talking about tickets, it’s more natural to say iki bilet or iki kişi için bilet, not typically iki kişilik bilet (unless it’s a special “two-person” ticket).

Is kişilik “personality” here?

No. kişilik can mean “personality,” but in iki kişilik it’s the capacity/for-use -lik suffix. Context disambiguates it.

Can I say iki kişilik bir yer instead?

Yes. Adding bir is fine: iki kişilik bir yer ayırtıyorum. It often sounds a bit more natural when you’re talking about a single item.

Does Bu akşam mean the showing is tonight, or that I’m making the reservation tonight?

As written, it most naturally modifies the time of your action: “I’m (doing the) reserving tonight.” If you want to say the reservation is for a showing tonight, make it explicit: Bu akşam için sinema … ayırtıyorum (“I’m reserving for tonight”).

Why use the present continuous (-ıyor) if this is about a future plan?

Turkish uses the present continuous (-(I)yor) for arrangements in the near future or actions that are in progress or imminent. Alternatives:

ayırtacağım = “I will reserve” (intention/plan, more future-oriented)
ayırtıyorum can imply “I’m reserving (now / shortly / it’s arranged).”

Could/should I use rezervasyon instead of yer ayırtmak?

All are used:

yer ayırtmak = native, common (“reserve a place/seat”)
rezervasyon yapmak = widely heard, but literally “to make a reservation”
rezervasyon yaptırmak = “to have a reservation made” (many prefer this because the venue does it) For cinemas, people also say bilet ayırtmak or simply bilet almak.

Is sinema için the best choice? What about sinemaya or sinemada?

sinema için = “for the cinema” (purpose) and is fine here.
sinemaya (dative “to the cinema”) or sinemada (locative “at the cinema”) are about destination/location, not purpose.
More natural in real life is to specify the movie: Bu akşam şu film için iki bilet ayırtıyorum / … şu filme iki bilet ayırtıyorum.

Can I move sinema için elsewhere in the sentence?

Yes, but keep modifiers close to what they modify and the verb at the end:

Sinema için bu akşam iki kişilik yer ayırtıyorum. (focus on “for the cinema”)
Bu akşam sinema için iki kişilik yer ayırtıyorum. (neutral) Avoid splitting iki kişilik from yer.

Why isn’t there a genitive before için (like “sinemanın için”)?

With nouns, için normally takes a bare noun: sinema için, Ali için, film için. With personal pronouns, you must use the genitive: benim için, senin için, onun için. So sinemanın için is not used.

Is yer the right word for the cinema? Should I say bilet instead?

Both are possible, but:

yer ayırtmak emphasizes reserving seats/places (common for theatre, buses, restaurants; OK for cinemas with assigned seating).
For cinemas, many speakers prefer bilet ayırtmak/almak (“reserve/buy tickets”), often specifying the film.

Do I need a plural like yerler because it’s for two people?

No. iki kişilik yer refers to one place with a two-person capacity (like a two-person table/seat). Use plural only if you’re reserving multiple separate places.

Where’s the subject? Can I add Ben?

The verb ending -um already marks 1st person singular, so the subject is implicit. You can add Ben for emphasis or contrast: Ben bu akşam … ayırtıyorum.

Why do I sometimes see a double t in the past, like ayırttım?

That’s just the past tense attaching to the stem that ends in t: ayırt- + -tı + -m → ayırttım (“I reserved”). It’s not an extra causative; it’s regular past-tense morphology.