Where does “Hej-Gêr” come from?

Hej-Gêr (Middle High German) comes from Latin -ger, from Latin gerere — second-person singular future passive indicative...

Ancestry of “Hej-Gêr”, step by step

Step	Language	Word	Meaning
1	Latin	-ger	Forms adjectives meaning “-bearing, -carrying”...
2	Latin	gerere	second-person singular future passive indicative...