I used to stick short spoken word extracts between tracks on compilation tapes ... any of these any use to you?
Billy Graham
Noam Chomsky
Aldous Huxley
Tony Hancock
Steptoe & Son
Ralph Rickardson reading Keats
R.S. Thomas
Johhny Morris - Bedtime Stories
Basil Brush
Goon Show
Sherlock Holmes (Rathbone & Bruce)
1st 4 radio episodes of Superman from 1930's radio show (mainly for the cereal adds in between)
Extracts from Shakespeare read by the 1964 RSC
The Sauna Swami speach from The Monkees film 'Head'