I was wondering who had the first talking/intelligent weapon and apparently it was the Sumerians: the Sumerian mace Sharur belonging to the god Ninurta (in texts from ~2000 BCE or earlier), which has a personality and converses with its owner.
Although if we are talking only swords, I think the earliest goes to the Irish:
The earliest clear literary example is Orna (or "Little Pale Green"), the sword of the Fomorian king Tethra in Irish mythology.