Learn Hardcore Turkish: Arkadaşıma hediye kartı aldım; ister kitap ister kahve seçebilir. - I bought a gift card for my friend; she can choose either a book or coffee.

The suffix -a/-e is the dative case, often used for the recipient/beneficiary: Arkadaşıma = to/for my friend. This is called the benefactive dative.
Arkadaşım için also means for my friend, but it frames it as purpose (for the sake of), not a recipient. Both are correct here; Arkadaşıma sounds a bit more like “I got my friend a gift card,” while Arkadaşım için is “I got a gift card for my friend (for their benefit).”

Who is the subject of seçebilir? Where is “he/she”?

Turkish is a pro‑drop language: subject pronouns are often omitted when clear from context. The implied subject of seçebilir is o (he/she), referring back to your friend. You could make it explicit with O ister kitap ister kahve seçebilir or Arkadaşım ister kitap ister kahve seçebilir, but it’s not necessary.

Is hediye kartı in the accusative? Why does kartı end in -ı?

No. Hediye kartı is a noun–noun compound meaning gift card. In such compounds, the head noun takes a 3rd‑person possessive ending: hediye (gift) + kart + -(s)ı → hediye kartı. That -ı is not accusative; it’s the possessive marker of the compound.

Why not hediye kartını aldım? What would that mean?

Hediye kartını adds the accusative -nı to the compound and makes it definite: “I bought the gift card (a specific one we both know about).” In your sentence you mean “a gift card,” so hediye kartı aldım (no accusative) is right.

Do I need to say bir hediye kartı?

You can, but you don’t have to. Bir hediye kartı aldım explicitly says “a gift card.” Without bir, the object is still indefinite and very natural in Turkish. Adding bir can add a slight sense of “one (single)” or introduce a new item in a narrative.

Does almak here mean “to buy”? Should I use satın almak?

Yes. Almak commonly means “to buy” in everyday Turkish. Satın almak is perfectly correct but a bit more formal/explicit. Hediye kartı aldım is what most people would say.

What does ister … ister … mean? Is it from istemek “to want”?

İster … ister … is a fixed correlative meaning “either … or … / whether … or ….” It’s not about wanting here; it’s a set connector. Alternatives: ya … ya (da) … or kitap veya/ya da kahve.

Do I have to repeat ister before both options?

Yes, that’s the standard pattern: ister X ister Y. Keeping it symmetrical sounds natural. With other connectors you can say ya kitap ya da kahve or kitap veya/ya da kahve.

Why don’t kitap and kahve take accusative -ı/-i after seçebilir? When would I add it?

Direct objects are unmarked (no -ı/-i) when they are indefinite/non‑specific, as here: (o) kitap/kahve seçebilir = can choose a book/coffee (in general).
Use accusative when the choices are specific/known: İster kitabı ister kahveyi seçebilir = can choose the book or the coffee (those particular ones we have in mind).

Could I say bir kahve here? Does that change the meaning?

You can say ister bir kitap ister bir kahve to highlight “one book or one coffee.” In café contexts, bir kahve is how you order “a coffee.” In your sentence, leaving them bare (kitap, kahve) is also natural and generic.

What exactly does seçebilir express—ability, permission, or possibility?

The -e/-a + bil- construction expresses can/be able to and, by context, can also imply permission or possibility.

seçebilir = can choose (able/allowed/possible).
Future ability: seçebilecek (will be able to choose).
Suggestion/let them: seçsin (let him/her choose).
If you mean “can buy” rather than “can choose,” use alabilir.

Why is there a semicolon? Could I use something else?

The semicolon neatly links two related independent clauses. You could also write:

Arkadaşıma hediye kartı aldım, ister kitap ister kahve seçebilir.
Arkadaşıma hediye kartı aldım; kitap veya kahve seçebilir.
Or split into two sentences. All are acceptable; the semicolon is just a stylistic choice.

Can I change the word order in the first clause?

Yes, Turkish word order is flexible. Neutral is object–verb near the end:

Neutral: Arkadaşıma (bir) hediye kartı aldım.
With focus on the recipient: (Bir) hediye kartı arkadaşıma aldım (I bought the gift card for my friend—emphasizing for whom). If you make the object definite (hediye kartını), moving it earlier often signals emphasis/contrast.

How would this change if the friend were plural?

Recipient: Arkadaşlarıma hediye kartı aldım (I bought my friends a gift card/gift cards).
Verb agreement: … seçebilirler is the explicit 3rd‑person plural:
Arkadaşlarıma hediye kartı aldım; ister kitap ister kahve seçebilirler.
In many contexts, seçebilir (without -ler) is also acceptable with a plural subject, but adding -ler is clearer.