The Speaking in Tongues article should not be used, without care, to group the languages of the Realms. As stated in the article, "Languages have been placed into language groups by comparing them to their closest real-world cultural counterparts (noted parenthetically after each language group) when possible. Thus Alzhedo, Midani, and Untheric were placed into the same language group, although they are still quite different from one another (as demonstrated by the nonweapon proficiency cost table). Everything else is invented."
This basically means that the article only put all three of those languages under the Untheric header because the author felt that the cultures which use those languages were all "à la Semitic: Assyrian, Babylonian, Modern Arabic" cultures. Lantanna is grouped with Durpari and the Imaskari languages used in the Hordelands because the flavor of the countries that use those languages are all "à la Altaic: Azerbaijani, Turkish, Mongol" in the author's mind.
If we keep those groupings, it implies a historic connection between those cultures which does not necessarily exist.
I can only assume that the author chose to group the languages that way based on the assumption that learning one similar-to-Egyptian language ought to be similar to learning another similar-to-Egyptian language. It was not based on Realsmlore, and I think it was an unfortunate approach to the article.
So that's why I'm deleting the reference to a connection between Untheric, Midani, and Alzhedo... the source article does not establish or support a Realmslore-based connection. :)