A word used primarily by grade-school children, "yabut" denotes the beginning of a rebuttal. It is very often used when speaking to authority figures, such as teachers and parents.
TEACHER: "Billy, you're out of your seat again. You know that you're never allowed out of your seat without permission."
BILLY: "Yabut I have a glandular problem."
Literally pronounced as "yeah-but" this under-articulated gem is the quick / lazy equivalent to the phrases: "yeah but...", "yeah but no", and "yes but no".
Commonly used among North-Eastern transplants living in the South-East, lazy speakers, and anyone who is flustered or having an argument in a hurry.
"These findings conclusively show that meth is bad for your health."
"Yabut, I like it."