This is an example of South Eastern U.S, country slang in it's most unrefined, yet commonplace, of forms. Mostly derived from/by repetition from those with little education due to poverty or simply the need for family/adolescence to work on farms or in cotton fields during harvest. Most rural area schools would close during harvest due to the need for most students to be absent.
Definition: (Have) you eaten yet? or (Have) you had supper
dinner yet? Pronounced as one word with 2 syllables, Ya'e't-yet?
Hungry?
