hundeahtatig [OE]
eighteti [MI]
eighty [ME]
éty
https://www.etymonline.com/word/eighty#etymonline_v_32178
https://www.merriam-webster.com/dictionary/eighty
https://quod.lib.umich.edu/m/middle-english-dictionary/dictionary/MED13157
https://bosworthtoller.com/19928