His voice was altered during the Grinch's speaking lines, giving him the voice we all know today.
https://www.youtube.com/watch?v=hqOOUJFv1n0Video can't be loaded because JavaScript is disabled: The Grinch Ending (Original 1966) (https://www.youtube.com/watch?v=hqOOUJFv1n0)
Thurl Ravenscroft provided the deep baritone voice for 'You're a Mean One, Mr[...]
