What's the correct way to write drawn-out vowels?

Question

How should I denote drawn-out vowels in English? If I have a character with speech disorder or with a very unique accent, what is the correct way to express, in written form, this quirk of their speech? Would it be appropriate to just repeat the vowel? Or perhaps there's a specific punctuation mark I am not aware of.

Answer 1

Yes, repeating the vowel is a common way to show that it is drawn-out. For example "caaat!" instead of "cat!"