At 9.30am GMT Tuesday 16 Jan there is a 15 min piece on the voice in Folk Song. It will look at voice specifically.

It is the second programme in a series of five the first being the Jazz Voice which can be heard on BBBC Radio 4 archive.
It was broadcast yesterday (9thJan) at 9.30am titled "The Singer not the Song"

Just listened to it again. Great stuff worth 15 mins of anybodies time