No surprise that it came from where Abraham came from (and close to where Noah's ark came to rest). Abraham was just a few generations from Noah. Hebrew (according to Joseph Smith), is just a hop, skip and a jump from the original Adamic language that Noah and his son Shem would have spoken.
Hebrew came from the Akkadian language.
Akkadian was spoken in Akkad which was just north of Sumer. Both places constituted greater “Mesopotamia” — the land between two rivers — the Tigris and Euphrates.
Akkadian is a Semitic language, I believe (as is Hebrew, obviously). But Sumerian is not a Semitic language. It’s an entirely different language family.
Akkadians and Akkad were eventually assimilated into Sumer. I imagine it much like the Scottish/English relationship.
Abraham was from Ur, which was is Sumer, but he was of Hebrew stock.