Etymology tree English autism Proto-Indo-European *-id- Proto-Indo-European *-yéti Proto-Indo-European *-idyéti Proto-Hellenic *-íďďō Ancient Greek -ῐ́ζω (-ĭ́zō) Proto-Hellenic *-tās Ancient Greek -τής (-tḗs) Ancient Greek -ῐστής (-ĭstḗs)bor. Latin -istader. Old French -istebor. Middle English -ist English -ist English autist From autism + -ist.