An onomatopoeia is a word that imitates sound. "Onomatopoeic" is often synonymous to "echoic" or "imitative". The plural form is "onomatopoeias" but it can also be used as an uncountable noun. So kaboom and buzz are onomatopoeias, but ...read more »
If you need to write a character with an accent, here is some useful advice from writer Rose Lerner, and over here more specifically about the Southern American accent.
Monday, April 01, 2013 onomatopoeia-writtensound.blogspot.com