Learn Hardcore Turkish: Ben bugün çay yerine kahve seçebilirim. - I can choose coffee instead of tea today.

You can drop it. The verb ending in seçebilirim already shows first-person singular. Keeping Ben adds emphasis or contrast, like “I (as opposed to others) can choose …” So both Ben bugün … and Bugün … are correct.

Where should bugün go in the sentence?

Time words usually come early. Natural options:

Bugün çay yerine kahve seçebilirim. (neutral, very common)
Ben bugün çay yerine kahve seçebilirim. (extra emphasis on “I”)
Çay yerine bugün kahve seçebilirim. (also fine; slightly different rhythm) Putting bugün at the very end (… seçebilirim bugün) is colloquial and more speech-like.

Why don’t kahve and çay have the accusative -i (like kahveyi, çayı)?

Because they’re not specific/definite here; you’re talking about coffee and tea in general. In Turkish, a definite direct object takes the accusative, an indefinite one doesn’t. If you mean specific items, use the accusative: Bugün çayın yerine kahveyi seçebilirim (“I can choose the coffee instead of the tea [that we have in mind]”).

What’s the difference between çay yerine and çayın yerine?

Both are correct. Bare X yerine is common and light in tone. X’in yerine (genitive) is a bit more explicit/literal (“in X’s place”), and is especially common with people/roles: Öğretmenin yerine derse girdim (“I took the class in place of the teacher”).

What exactly does yerine mean and how else can I use it?

It’s a postposition meaning “instead of / in place of.” It can follow nouns or verbal nouns:

Nouns: Çay yerine kahve (“coffee instead of tea”)
Verbs: Çay içmek yerine kahve içebilirim (“I can drink coffee instead of drinking tea”) With people/roles, genitive is common: Onun yerine ben gittim (“I went in his/her place”).

How is seçebilirim formed?

Root: seç- (“choose”)
Potential: -(y)ebil- (“can/be able to”) → seçebil-
Aorist/present: -ir
1st person singular: -im Result: seç-ebil-ir-im = “I can/may choose.”

What’s the difference between seçebilirim, seçerim, and seçeceğim?

Seçebilirim: ability/possibility or a soft, non-committal future (“I can/might choose”).
Seçerim: aorist; habitual or a firm, decided intention (“I choose / I will choose (I promise)”).
Seçeceğim: future tense; a clear plan/intention (“I will choose”).

How do I ask “Can I choose coffee instead of tea today?” politely?

Use the question form of the potential: Bugün çay yerine kahve seçebilir miyim? In a café, … kahve alabilir miyim? is even more natural: Bugün çay yerine kahve alabilir miyim? (“May I have coffee instead of tea today?”)

How do I negate or soften the meaning (can’t, may not, don’t)?

“I can’t choose …”: … seçemem.
“I may not choose …”: … seçmeyebilirim.
Habitual negative (“I don’t choose …”): … seçmem.
Future negative (“I won’t choose …”): … seçmeyeceğim. Avoid using değil with verbs; use verbal negatives instead.

Can you show the full conjugation of seçebilmek in the present/aorist?

Ben: seçebilirim
Sen: seçebilirsin
O: seçebilir
Biz: seçebiliriz
Siz: seçebilirsiniz
Onlar: seçebilirler (often just seçebilir in speech)

Is seçmek the most natural verb here, or would Turks say something else?

Seçmek is fine, but in everyday contexts:

Ordering/getting: almak → Bugün çay yerine kahve alabilirim.
Saying what you’ll drink: içmek → Bugün çay yerine kahve içeceğim.
Expressing preference: tercih etmek → Bugün çay yerine kahveyi tercih edebilirim/ederim.

Can I switch the order around, like “kahveyi çayın yerine seçebilirim”?

Yes, that’s grammatical: Bugün kahveyi çayın yerine seçebilirim. The default, most neutral order keeps the “instead-of” phrase right before what you choose: … çay yerine kahve seçebilirim. Don’t split X yerine from what it modifies too much, or it can sound clunky.

Should I add bir (“a”) before kahve?

Only if you mean “one coffee” as a countable item (e.g., ordering): Bugün çay yerine bir kahve alabilirim. In your original sentence, you’re talking about coffee as a type/category, so no bir.

Does yerine also work with people, like “instead of him/her”?

Yes: Onun yerine ben gidebilirim (“I can go instead of him/her”). With people/roles, the genitive (-in/-ın) is very common: Ayşe’nin yerine Mehmet sunum yaptı.

Any quick pronunciation/stress tips for this sentence?

ç = “ch” in “church” (çay, seç-)
ğ isn’t in this sentence; h in kahve is a real h.
ü in bugün is the front rounded vowel (like German “ü”).
Word stress is usually on the last syllable: se-çe-be-li-RİM; bu-GÜN; kah-VE; çeç? Actually seç- is “sech.” The whole sentence naturally stresses the verb at the end.