What is the origin of the personal pronouns I, you, he, she, it, we, and they?
I haven't got time to take them all the way (or to check references, so this is from memory), but yes they do go back to PIE, with the possible exception of she. But they come by different routes.
- I from Old English ic, ultimately from PIE eghom.
- You is historically the object case of ye, cognate with German euch, and Sanskrit yuyam. Note that these are plural: the singular thou has dropped out of use in most English dialects.
- He is certainly common Germanic (Cf Swedish hän) and I think it goes back to the same root as Latin is.
- She is another word that came in after the Old English period, but I think it's cognate with German sie. I'm not sure of its earlier history.
- We is also Germanic (German wir), but I don't recall its older history offhand.
- They is Old Norse, and replaced Old English hie. It goes back to the same demonstrative root as that.
I hope somebody has time to expand my random recollections.