Learn Hardcore Turkish: Telefon çalıp duruyor; kim arıyor acaba? - The phone keeps ringing; I wonder who is calling.

It means keeps ringing / won’t stop ringing. The -ıp durmak construction expresses repeated or ongoing action, often with a slight nuance of annoyance. So Telefon çalıp duruyor ≈ The phone keeps ringing, not just The phone is ringing.

Why is it çalıp and not çalip or çalıyor?

çalıp uses the converb suffix -ıp/-ip/-up/-üp, which links verbs (roughly “doing X and …”). After a/ı, it becomes -ıp, hence çal-ıp.
It can’t be çalip because of vowel harmony; a pairs with ı, not i.
It’s not çalıyor because the structure here is çal-ıp dur-uyor (“ring and keep on”).

Does durmak not mean “to stop”? How does duruyor end up meaning “keeps …ing”?

Alone, durmak means “to stop/stand/stay.” In the pattern V-ıp durmak, it functions aspectually: “to keep doing V (repeatedly/continuously).” So çalıp duruyor is an idiomatic periphrasis, not rings and stops.

How is çalıp duruyor different from çalmaya devam ediyor or just çalıyor?

çalıp duruyor: repetitive/continuous, often slightly annoyed.
çalmaya devam ediyor: neutral continues to ring (more formal).
çalıyor: simple is ringing (no extra nuance). Similar colloquial options: sürekli çalıyor, susmuyor (won’t be quiet), çalıyor da çalıyor (keeps on and on).

What does acaba add? Can I leave it out or move it?

acaba expresses wonder/uncertainty and softens the question. Without it, Kim arıyor? is more direct. Placement:

Acaba kim arıyor? (common)
Kim arıyor acaba? (very common, conversational) Both are natural; meaning is essentially the same.

Why isn’t the question particle mi used here?

mi/mı/mu/mü forms yes/no questions. With a wh-word like kim (who), you don’t add mi. Compare:

Kim arıyor? = Who is calling?
Arıyor mu? = Is someone calling?

What’s the difference between kim arıyor and kimi arıyor?

Kim arıyor? Subject unknown: Who is calling?
Kimi arıyor? Object unknown (accusative kimi): Whom is he/she calling?

Could it be kimler arıyor? Why is the verb singular?

Kim takes a singular verb: Kim arıyor? If you suspect multiple callers or want a more general/polite tone, you can say Kimler arıyor? (“who all is calling?”), but the singular is the default.

Is there any ambiguity with çalmak meaning “to steal”?

Context and case marking resolve it:

Telefon çalıyor / Telefon çalıp duruyor: the phone is ringing / keeps ringing.
Telefonu çaldı: he/she stole the phone (accusative -u).
For instruments: piyano çalmak = to play the piano.

How are arıyor and duruyor formed? What’s the role of vowel harmony?

aramak → arıyor (stem ara-
- present continuous -(I)yor; last vowel is back unrounded, so I = ı).
durmak → duruyor (stem dur-
- -uyor; last vowel u → u). The vowel in -(I)yor changes by harmony (ı/i/u/ü); the -yor part itself stays yor.

Why a semicolon here? Could it be a comma or a period?

The clauses are closely related, so a semicolon is stylistically neat. You could also write:

Telefon çalıp duruyor, kim arıyor acaba?
Telefon çalıp duruyor. Kim arıyor acaba? All are acceptable, especially in informal writing.

Any pronunciation tips for this sentence?

ç = ch (as in English “chip”).
ı (dotless) in çalıp, arıyor = central vowel (like the a in “sofa”).
ö in telefon = German ö / French eu.
-yor = “yor” with a short o; stress typically falls on the last syllable: tele-FON, du-ru-YOR, a-rı-YOR.

Could I say Telefon çalıyor instead? What changes?

Yes. Telefon çalıyor is neutral The phone is ringing (now). Telefon çalıp duruyor adds that it keeps ringing—repeatedly, and perhaps annoyingly.

Can you break the sentence down morphologically?

Telefon: phone (subject)
çal-ıp: ring + converb -ıp (…and)
dur-uyor: stay/keep + present continuous -(I)yor
;
kim: who
ar-ıyor: call + -(I)yor
acaba: I wonder / perhaps (softener)