-Tseng = Tseng.
-Heidegger = Hi-degger
-Sephiroth= Sefiroth
-Bugenhagen= Bugenhagen
-Elmyra= Elmyra

They aren't really hard to pronounce, at least for me.

Se-fi-ros
It's still a 'th' sound at the end there. They use the 's' and 'th' sound interchangeably.