I neve really thought about what language Abraham spoke. Did Noah speak Sumerian, too?
Best ancient Sumerian story is still current among the Sa'ami and Chuchi ~ it's a lesson. The deal is that a mother who doesn't tend to her daughters' needs for husbands might find herself turned to stone and then they'll have to sleep with their father to have children.
This same story, over 7,000 years old, may be found in petroglyphs in Finland. It's covered in a couple of websites.
To make a long story short, the 9 Sa'ami languages have one additional cognate language ~ and that's ancient Sumerian, and possibly one Indian language in California.
So, there you have the story of Lot's wife and Lot's daughters ~ pretty ancient stuff ~ and thousands of years before Abram became Abraham. No doubt he knew that story well, and the various Sumerian versions. Odds are he had it written on tablets kept in a box his followers and herdsmen carried around with them on their journies through the ancient world.