Has anyone looked into the word used for language here?
It is not the standard one used of languages in the Hebrew scriptures.
The word used for language throughout Genesis 11 is שָׂפָה (“lip”) not the usual לָשׁוֹן (“tongue”). From what I can tell — do a concordance search yourself and see! — שָׂפָה typically refers metaphorically to speech (i.e., the content or moral quality of what is said), not to the cultural-linguistic idiom (e.g., Hebrew vs. Akkadian, etc.). I’m having a hard time pinning down a single context where שָׂפָה unequivocally refers to the language. (Even in Is. 19:18, a possible counterexample, it could easily refer to cultic, rather than linguistic, differences.)
Compare this with Genesis 10:5, 20, and 31, which uses לָשׁוֹן: “From these the coastlands of the nations were separated into their lands, every one according to his LANGUAGE, according to their families, into their nations” (v.5), and sim. in the other two verses. Unlike Genesis 11, this seems to function unequivocally as an etiology of linguistic diversity.
To me, it seems that languages (לָשׁוֹן) were diversified in Genesis 10, and Genesis 11 has Babel imposing a single religious/cultic idiom (שָׂפָה) on all this diversity.
I originally posted this as a comment on RJS’s post on Babel on Jesus Creed back in 2014, but got little discussion at the time. Here’s the link, which describes J. Richard Middleton’s perspective on Babel: