As a player of a modern cittern I find this very interesting - it is, as other posters have said, a totally different instrument and the different tunings and playing styles allow a unique and personal approach to the music, which is one of the reasons I like it.

Paul Hathway makes a 10-string English Guitar, an 8-string Early Cittern and a 12-string Bell Cittern. His website also gives a brief background to each of these instruments:

www.paulhathway.com

BTW, I can recommend Paul's instruments; we have a mandolin and octave mando by him.