Illithid learning languages

Relevant lore for reason for bug:

Illithids primarily communicate through telepathy. Drawing and implanting

thoughts within the minds of others is as easy as breathing to them, and

they can understand each and every language. This is because illithids, when

conversing, do not listen to the words, but to thoughts and mind patterns

which form these words. In turn, their own telepathic words are thought

patterns which they implant into the target's brain, which translates them

into an intelligible tongue. The one exception to this is the secret languages

of the undead and the vampires; the Continuum shields their minds, preventing

the illithid from simply plucking the thoughts out of their skulls.

8 minutes ago, Archbishop Monk said:

I learned demonic from someone in Nexus at the time. Dezlo maybe?

We'll look into this as well, but this should not have been possible.  Demonic is one of the languages that cannot be learned.  No telepathic language can.

I know this is old, but I'll explain it:

Illithid can hear all languages, but can't speak all of them (unless they know them). They can learn all languages, except gated ones like demonic. Thulgan likely taught it to you through an Immortal, since Thulgan probably quested for it.