You're right, that in some dialects it is different. But to most English dialects, "can't" and "cunt" have completely different vowels, and the length isn't dis

You're right, that in some dialects it is different. But to most English dialects, "can't" and "cunt" have completely different vowels, and the length isn't distinguished. "Lose" and "loose" are also distinguished by the voicing, "lose" ends with /z/ and "loose" ends with /s/. Maybe not all dialects.