Lien is obviously the hostage, but why do their grammar lessons need to be from a hostage? It may be Therkla teaching them as part of a plot against Hinjo. Or they may be just self-teaching themselves with Common for Dummies.
I love Banjo. I'm still bitter my last DM didn't let my bard take Leadership and get a cleric cohort that worshiped Banjo. Think of the comedic relief!!