How to pronounce the sigma correctly? Where is the tongue exactly when pronouncing?

Question

The Σίγμα is clearly different from the english S or the german. Sometimes it even sounds slightly like a 'sh'. So where exactly is the tongue when pronouncing it? Are the teeth closed and is the tongue up as I assume?

Answer 1

The best answer is to listen to the experts in the field pronounce Greek and Latin - and model your pronunciation on theirs.

http://atticgreek.org/pronunc/sigmaU.html