Where does “si” come from?

si (Middle High German) comes from Old High German siu, from Proto-West Germanic sī, from Proto-Germanic sī, from Proto-Indo-European sih₂, from Proto-Indo-European -ih₂, from Proto-Indo-European -h₂ — Creates collective nouns, which refer to groups...

Ancestry of “si”, step by step

StepLanguageWordMeaning
1Old High Germansiu—
2Proto-West Germanicsīshe, it
3Proto-Germanicsī—
4Proto-Indo-Europeansih₂she
5Proto-Indo-European-ih₂Feminizes athematic nominal stems
6Proto-Indo-European-h₂Creates collective nouns, which refer to groups...
Every word from Proto-Indo-European -h₂ →Every word from Proto-Indo-European -ih₂ →Every word from Proto-Indo-European sih₂ →