Scooby-Doo the series and the billing, in an attempt to boost "Scooby-Doo"s slipping ratings. The 1979–80 episodes, aired under the new title "Scooby-Doo and Scrappy-Doo" as an independent half-hour show, succeeded in regenerating interest in the show. Lennie Weinrib voiced Scrappy in the 1979–80 episodes, with Don Messick assuming the role thereafter. Marla Frumkin replaced Pat Stevens as the voice of Velma mid-season. As a result of "Scooby-Doo and Scrappy-Doo's" success, the entire show was overhauled in 1980 to focus more upon Scrappy-Doo. At this time, Scooby-Doo started to walk and run anthropomorphically on two feet more often, rather than on
Scooby-Doo (character) series and movies. Scooby has a speech impediment and tends to pronounce most words as if they begin with an "R"; however, most characters are able to understand him almost perfectly. In most iterations, he keeps his sentences relatively short, usually using charades for anything longer than three or four words. His catchphrase, usually howled at the end of every production, is "Scooby-Dooby-Doo!" or "Rooby-Rooby-Roo". Scooby was voiced by Don Messick through "Arabian Nights" in 1994, after which point Messick quit smoking; quitting smoking changed his voice and prevented him from achieving the same raspy vocal effect (despite Messick's efforts,