Since Akkadian had become the dominant language in Mesopotamia, including in cities like Ur, sometime around the second millennium BC, isn’t it quite possible that Abram and his father spoke Akkadian and thereby would be considered Semitic since Akkadian is a Semitic language
The Akkadians in the northern cities of Sumer were a different people than the Sumerians of the southern cities. They were a semetic people. The Sumerians were not a semetic people. Ur of the Chaldes was a Sumerian city. That’s where Abrahams father was from. That’s what it says in the bible. And he left Ur at the time of Ur’s fall.
No one knows what language Abram’s father spoke.