WHAT IS DAVID TRYING TO SAY!!!!!!!!!!!!!!!!!!!!

On page 138 I don't get what David is suppose to say.
(Quote) David had the box open and was already sifting through the pieces. "Aaaa a gou wwwone, Wobbad."
What is he suppose to say??????????
I think the author should put ( ) beside Davids parts and write what he actually is trying to say TO MAKE the reader MORE CLEAR!!!!