I love stuff like this. Almost every Monday on the BBC London radio
show they have a professor of linguistics (Laura Wright) talking about
some aspect of London language. This Monday they were talking about
children's "truce terms", and then moved on to why words changed from
"F" to "V".
If you'd like to listen to it, go to:
then scroll down the list to "Robert Elms" and click on MONDAY beneath
his name; then click on the 5 minutes/15 minutes on the left of the
screen until you get to 01.39.30 into the show.
If things, don't work download the BBC Player from the site, which is
NB this episode is only there until next Monday.