Real Languages in D&D, is this idea a good one, or not worth it

[Eldariel]

Yes. So
Celestial = Hebrew
Infernal = Backwards Latin
Abyssal = Backwards Rock and Roll
Draconic = Latin


btw Eldariel: 70 years != always.

I'm not sure what you're referring to. The Blood War? It's been on for long enough. Religious wars? These particular ones since the birth of Islam.