What I'd like to know is, how often does it happen that a monster that normally shouldn't be able to speak speaks in OotS, or a monster that normally only speaks a different language speaks Common in OotS? Here are some possible examples, but there may be more that I don't recall right now.
- Displacer beasts. Do they normally speak in D&D 3.5?
- Should a Flumph normally be able to speak in a way that this humanoid therapist understands?
- Are these Ogres speaking in Common, or do they speak Giant but Roy and Haley both have that as bonus languages?
- This human zombie is repeating “your fault”, can they normally do that?
- I'm pretty sure fiendish roaches shouldn't be able to speak, but maybe the demon roaches aren't fiendish animals but some other kind of creatures.