Death Lives - S3-E6
Corrected entry: When Peter is in the van with Cleveland, Cleveland's voice is slow and how it normally is, except it shouldn't be. In another episode, Peter recounted that Cleveland was an auctioneer and was hit with an antique which made his voice slow.
Correction: Being a caller at an auction is a skill that needs to be learned. Since Cleveland originally spoke slowly, it's more likely that he began to speak faster once trained as an auctioneer, but the antique hitting him made him revert to his normal slow speaking voice.
rswarrior