What is the difference between Shaman, Witch and Gwyddon?

Shaman is a Mongolian term.
Witch comes from wicce – to bend in Saxon and is English.

Gwyddon is a Welsh term and in modern Welsh translates as ‘scientist’.  In Old Welsh as ‘wise one’.

All are traditional healer priestesses/priests who communicate with the spirit world and use ritual and natural materials to effect healing and transform situations.

Each uses their culturally unique system which, because these are wise pragmatic practitioners, has over millennia absorbed and borrowed external data that has been tested empirically and found harmonious with their core practices.  Each is rooted in its land of origin and most effective there.  Some travel better than others e.g. Egyptian systems harmonise well in Africa, Europe and the Near East.  Voodun is best left to African, Caribbean and South and Central American peoples.  To work effectively beyond our land and culture we need to create special temples and this complication is against the spirit of Natural Magic.

To ascribe a hierarchy of authenticity is to limit our understanding.

There are many practices they have in common e.g. achieving trance communication with the spirit world through chanting, dancing and repetitive actions.  We can see the much diluted remnants of these routes to divine ecstasy in all the major mainstream religions e.g. monastic plain chant.