Must have been delirious: found his link in 2 second, took me about an hour to type that nonsense above
http://www.omniglot.com/writing/ogham.htm
Not sure, my only source on information is a small book called "THe Celtic Tree Oracle," by Liz and Colin Murry, read it wow 20 years ago when I was keen on Celtic History, but not read it again till now, they mention it as Druid Language, but what do I know

They also mention Ovates and Bards knowing it, also a form of sign language using differant part of hand and fingers to represent letters.