Wow,

Much thanks to everyone - lots to consider.

Definitely get more info without the T !

Response at sessions ? Good point. I usually play/sing slow quiet miserable songs - so something lively or evocative would make a nice change for the audience. I think several of the experienced players could 'get it' fairly quickly, if not - it was a challenge for 'em.
The sessions that I would play at tend to be pretty easy going, I usually wouldn't play at the 'we don't allow ....' sessions.

I had heard that most Klezmer music derived from music used as part of the religious services, which is why I intend to be careful about which tunes to try. Lots of good resources posted - thank you all - will research.

A question for those who know - does the word Klezmer really derive from 2 Hebrew words : kley(instrument) & zemer(song) ?