Virgil ponders before answering, perhaps ponders too long, as many of his answers and thoughts are spoken before he's drawn the breath to speak them, but then does concur, "From what I recall of the few texts there are, and that I have been fortunate enough to read, documenting the ruins and culture of Netheril, it was a civilization strongly focused around magic, primarily the arcane sort. So it would stand to reason, that much like now, the wizards of olde used Draconic in their magical arts, perhaps even more so than now. IF we are to believe the lore of the Dragon Fall war, the first reasoning sentient beings in the Prime Material, with magic, were dragons, even before primitive elves began to develop magical potential. As for speaking Netherese? To best of my knowledge, the language hasn't been spoken for centuries. So unless it is Draconic..." he pauses to glance aside to the two Redspawn, an obvious silent suggestion they would be the most fluent, since it's their primary language, then finishes, "... the only way I know to dig up centuries old extinct languages, is to ask a being that's just as old, or older still. Since Baatezu and I don't get on very well, I know of only one being older than all the Tanar'ri that is not an enemy of my errr... 'owner'." Delicate that last part, as he tries to not unsettle paladin and cleric unnecessarily. There is, after all, no easy way to admit to being cursed, and claimed property of Abyssal Royalty, without upsetting such people, and the common rabble.
A pause he gives, bracing himself for the possibility of having to make that deal for information, then shrugs and steps away from this puzzle, idly wondering if one of his higher tier Invocations couldn't be used to just break through.
Primary (Pheurazath AKA Kalkyril Ilindl)
Secondary (Virgil Stahne -- A repentant Warlock)
Other Secondary (Skrach -- A rogue, a rat, touched by the best)