I checked on Forvo.com, and in the one example there the pronunciation there was the same as on Duolingo with the "ζ" being pronounced like the French "j" or the Russian "ж" and not like the English "z".
Hi- how do I get the greek keyboard? Even though I managed to get it as atb on my tool bar, I can't work out how to use it. Surely I would need an on screen keyboard? As my laptop obviously has the English alphabet on it!!