Learn Hardcore Turkish: Otobüs gecikmiş. - Apparently, the bus is delayed.

The suffix -miş is the evidential/indirect past. It signals that the speaker learned the information indirectly (hearsay) or inferred it from evidence. So Otobüs gecikmiş means “The bus is (apparently) delayed / has been delayed,” with a nuance of “it seems” or “I heard.”

How is gecikmiş different from gecikti?

gecikti (simple past) = “it was delayed/it got delayed,” and you present it as a known fact (you witnessed it or are stating it directly).
gecikmiş (evidential past) = “it’s apparently/it seems it was delayed,” suggesting you found out or inferred it.

Can gecikmiş also mean “it seems/appears to be delayed”?

Yes. The evidential -miş often maps to English “apparently/seemingly.” You can read Otobüs gecikmiş as “It seems the bus is delayed.”

Is gecikmiş a verb or an adjective here?

Here it’s a finite verb form (predicate) in the evidential past: gecik- + -miş. In other contexts, gecikmiş can be a participle meaning “delayed,” as in gecikmiş otobüs (“the delayed bus”).

Where is the “to be” verb in this sentence?