Westeros sounds similar to /west of us/. It also sounds like a relaxed pronunciation of west of Essos might sound. It seems plausible that Essosians might have first called the continent West of Essos, then elided and slurred the pronunciation to /westeros/.

Likewise, the name for the continent south of Essos, Sothoroyos, sounds similar to /south of us/ and to /south of essos/.

I suspect other people have noticed this.

Has GRRM ever written or spoken about the etymologies of Westeros and Sothoroyos?