quoting Izambri, Duke, the Findible League:

Bèrs tant aget Aléspanikarha, Amídtale Hiarmentnicatze. Al(e)– im lhaonze a menaveu è lheraimí te se lamne èu ringlia.
Aléspanikarha is a pretty word, Rhetorica. I guess that al(e)– stands for “no, not” and that the language is Lilitika.

Zú—alé- + Hispanía + -ika + -arha. Lilitika Ketalàn vóe, dúrafa sotana deke-Doisseia.
Yes—not + Spain + way-of + ACC.F.SING. It's Nomad's Lilitika, the last pre-settlement argolect.

Not sure about the handling of Germanic languages. It seems to me they'd survive better on the periphery, like in Britain and Scandinavia, rather than in the heart of the continent, much as the Celtic languages survived in insular environments IRL. German would probably have been an endangered language at this point: the invaders would be arriving in Europe at a time when the Holy Roman Empire was at its maximum extent, and Latin was at maximum prestige, so only peasants spoke MHG at the time (not OHG—that would've transitioned mid-11th millennium due to a major sound shift.) Remember, Mozart's operas (some 500 years later) were considered against the grain because they were in German.

(Alternatively, you may be subtly trying to block Rome proper from expanding into Germania when it did. Why not go the whole way and make Basque country cover the whole Iberian, then?)

Apologies if any of the above is eye-rollingly obvious. I have no clue what your credentials are when it comes to Germanic languages.

quoting con quesa, Layperson, California:

Also I reject your claim that a language having /ɾ/ as it's only liquid is "weeby". Lots of languages lack /l/.

Sure—but these two statements can coexist. The tongue-in-cheek insinuation comes down to a matter of the motivation for only including one liquid/approximant/trill/etc. As I understand it, the Berber languages are generally pretty rich in this area, so the inspiration isn't immediately apparent.

I also think that talking about how the writing system (if one exists) ought to work is a bit premature,

Divergence between a written language and its spoken counterpart can fossilize etymological relationships that would otherwise be less obvious, e.g. any fluent English speaker could intuit a definition for "complication" by back-forming from "relation", "relate", and "complicate", essentially intuiting what "-tion" does. But the homophone "shun" is of no help at all. (And if that doesn't convince you, just think about how many homophones French has...)

In short, I'm arguing against generating morphemes based purely on phonology. Assuming the culture is highly literate, the written form of the language shouldn't match 1:1, and if we were to, for example, just use IPA to create the language and completely forgo any attempt at an official transliteration, the result would be like Tok Pisin, or some other really immature creole—which is very unlikely to have a phonological inventory as rich as the one proposed.