I agree an Irish and Scottish accents are good stand-ins for Halethian, Dunlending, Enedwaith, and so forth.
Taliska was originally invented and conceived as the language of both the Halethians and Beorians, because originally the Beorians were related to the Halethians instead of the Hadorians. When Tolkien changed the Beorians to be related to the Hadorians instead, presumably Taliska became only the Halethian language. Beorian must be related to Adunaic, which Taliska is not. The most Halethian words that I know of in later writings appears in The Wanderings of Hurin, but not enough of the earlier Taliska concept has been published yet for me to compare them directly. The plural ending -in is the only thing I know for certain that they share.
The weird thing is that, when English usually represents Elvish languages (in the First Age) it makes sense for Khuzdul and Adunaic accents to be represented with two different Semitic accents. But in the Second and Third Age, when English usually stands in for Westron, it makes sense for people like the Rohirrim and Men of Dale, or the speakers of Beorian-related languages, to speak Germanic languages such as Anglo-Saxon and Frisian and Old Norse. If we continue putting our frame in the Third Age and Fourth Age, setting up a contrast (between Semitic accents = Adunaic speakers, and Germanic languages = Adunaic related languages) would potentially create a clash within a single episode or a single season. So I think it may be better to just pick Germanic accents for the Hadorian, Beorian, Rohirrim, and related people, even during the First Age.
I've never seen the name Magol or Mago. I've seen the names (and nothing else) of Mørk and Hvendi, but AFAIK those languages have not been published. I am really curious what Magol/Mago is and anything you know about it ... whether it has been published yet, who spoke it, when Tolkien created it, what it sounds like... Is it the direct ancestor of Adunaic?