"İki bir sayı."
Translation:Two is a number.
You're right. If I hadn't seen the written sentence, I wouldn't have understood the recording.
I still struggle with when 'bir' is optional. How about this case. Is it mandatory or optional? Or put differently, what would 'iki sayi' mean (yes, the last i shouldn't have a dot, but i don't have a turkish keyboard at hand) - or would that be grammatically nonsensical?