Inside Out is a helpful example to look at when thinking about character voice or developing characters in general. In the script (and the film) the characters are emotions literally embodied.

Here, Sadness interacts with Joy and their “emotions” influence their way of talking. Note: Joy is quicker and more peppy in her word choice and Sadness uses words that feel more slow and sparse.

It’s useful to think about how word choice can influence the energy of a character and vice-versa.