The fictional place name "Yoknapatawpha" is typically pronounced as "yok-nuh-puh-taw-fuh". It's a name created by the American author William Faulkner for his novels and short stories, set in a fictional county in Mississippi. The name has its roots in the Chickasaw language and is meant to evoke a sense of the South and its history.

I don’t have ipa on this phone, but I would say it: Yock nap er (schwa) tor far

I don't want to post links because sometimes italki doesn't like that. However, if you go to youtube and search on the phrase "Yoknapatawpha County," you will find a recording of author William Faulkner pronouncing it and explaining it himself. "How do you pronounce the name of your mythical county?" "If you break it down into syllables, it's simple: Y-o-k, n-a, p-a, t-a-w, p-h-a. YOK-na-pa-TAW-pha. It's a Chickasaw Indian word, meaning water runs slow through flat land."

Looks like American Indian. I think it would be Yōk-na-pat-a-wop-fa