One of the first classes we had was an improv class. The point of the class was to get us to think more freely about characters and personalities, and to help us find a more dynamic and organic approach to creating them.
We were given exercises where we had to keep saying the same word or phrase in a circle, which was meant to make us think about all the ways the intonation and delivery of the words that someone could use. It also reminded me that the way the words are delivered is almost as important as the words themselves.
There were a lot of other exercises, from a form of charades to acting out some improv situations given to us without letting us discuss it beforehand to coming up with a full-on improv stage act where we had to come up with a basic storyline.
The one that stuck with me most, however, was the vocal exercise, as it seemed like the most vital bit to nail in a chatbot that would only be interacted with through voice.