Where does “do” come from?

do (Middle Dutch) comes from Old Dutch thī, from Proto-Germanic þiz, from Proto-Indo-European te, from Proto-Indo-European túh₂ — you, thou.

Ancestry of “do”, step by step

StepLanguageWordMeaning
1Old Dutchthī—
2Proto-Germanicþizdative/instrumental of *þū
3Proto-Indo-Europeanteclitic accusative of *túh₂: thee
4Proto-Indo-Europeantúh₂you, thou
Every word from Proto-Indo-European túh₂ →Every word from Proto-Indo-European te →Every word from Proto-Germanic þiz →