Well, you'd have to do your singing in concert with another person, I imagine, to handle the talking for you. Though perhaps clearing their heads might be enough to make them realize, themselves, that something is off.

Do we have any leads on who exactly are the titans behind this? Besides Matthew, I mean. It's entirely possible others involved are also Travelers, someone we know, since in many cases like this important roles are taken up by people the Arcana can manipulate to some extent.