The Koasati alphabet is largely based on the English one. It consists of 20 letters or combinations of letters. Vowels may be short (held for only a short time) or long (drawn out). There are three short vowels: a, pronounced as in English “sofa,” i as in English “knit,” and o as in English “coat.” Long vowels are spelled by doubling the letter, as in oola—or “town.” For instance there is a, as in aha or “sweet potato” and there is aa which is used to spell aati, or “person.”
Some vowels are nasal, denoted by underlining: a, i, o.
The consonants are easier, with the following letters almost the same in Koasati and English: b, ch, f, h, l, m, n, s, w and y.
There is one sound in Koasati that doesn’t exist at all in English. The sound is pronounced by saying l while making the air go over the sides of the tongue. It’s written as th. Examples include thato (“fish”), thafi (“winter”), and thaana (“horsefly”).