I collect all kinds of spoken word recordings, especially language learning tapes. One-off microphone recordings on unlabelled reels and cassettes form most of my collection, you can see and hear some of the collection
here and some of the resultant artwork made with the sounds
here.
I have lots of fascinating (to me anyway!) taped letters from the age before widespread domestic telephones. Like little time capsules.
I have been contacted a few times by UK radio producers interested in the material but then nothing more came of it. Anyone interested in found sounds would be well advised to listen to
Radio On Berlin.
I also have a few radio recordings like Radio Caroline and Luxemburg, Fluff, etc. and numerous BBC Schools recordings like History in Evidence, Drama Workshop and Time To Move.
Conicidentally Hamishboxer, I also have some Sunshine Radio and GLTK stuff, mostly jingles, picked up from a car boot sale in Knutsford decades ago! We'll have to compare 'em!