You know the message cantrip. You can also cast comprehend languages once with this trait, and you regain the ability to cast it when you finish a short or long rest. Starting at 3rd level, you can cast the magic mouth spell with this trait, and you regain the ability to cast it when you finish a long rest. Intelligence is your spellcasting ability for these spells.
When you make an Intelligence (History) check or an ability check using calligrapher's supplies, you can roll a d4 and add the number rolled to the ability check.
You have advantage on all Intelligence, Wisdom, and Charisma saving throws against magic.