An Etymological Dictionary of the German Language/Annotated/man
man, pronoun, ‘one, they, people,’ from Middle High German and Old High German man; corresponding to Old Saxon and Anglo-Saxon man, Dutch men; properly nominative singular of the Modern High German substantive Mann, ‘homo’; so too Latin homo appears as a pronoun in French on (as well as homme). In the early periods (Middle High German, Old High German, and Anglo-Saxon) man was again represented by the 3rd personal pronoun singular (Middle High German and Old High German ër, Anglo-Saxon hê); hence man is literally ‘any man’; in Gothic manna is found only with a negation (ni manna, ‘nobody’); see jemand. The singular may have here a collective meaning, just as Sanscrit mánus (compare Mann), and pûrús in the singular signify ‘person, people, mankind.’