also from August 2010. I originally made this as a reference for myself.
admittedly, way too different speech bubbles and fonts can come across as gimmicky, and on the converse side, one of the fascinating aspects of comics is especially with mystery stuff, it can be genuinely surprising to find out the source of a mysterious voice and such, etc. but I guess if there are a lot of off panel dialogue (which is also gimmicky and annoying?? maybe it could be used as a way to avoid talking heads) or if a character is special, etc., the speech bubble differentiation sort of thing may have its benefits?? hmm.