New Communication College Spell

[Astromancer]

It seems to me that once you have FOOLISHNESS and GIBBERISH, other spells to more subtlety foul and warp communication are logical.

A spell that subtlely warps body language and vocal intonation in such a way as to make the target of the spell seem sneaky and dishonest would have many uses in a game of intrigue.

Making the person who is giving your foe the correct military intelligence seem like a gullible dolt while making the ones giving the doctored intel seem sly and insightful has uses too.

[Pursuivant]

I'd base a Gibberish spell on the Strike Dumb spell. The fact that the subject(s) can still make meaningless noise and can communicate via non-verbal means is just a special effect.

A hypothetical Aphasia spell, where the subject can neither speak nor understand language of any sort, would better match the proposed energy costs and prerequisite chain. Essentially, Strike Dumb plus a limited form of Strike Deaf.