I know she died at a relatively young age, but are there any recorded speeches she gave? If not, what's the next best step in terms of finding valid information about her rhetoric? Thanks in advance, I appreciate any help I can get.
The trial record is the closest thing we have to Joan's voice.
By way of English: Daniel Hobbins' translation The Trial of Joan of Arc is very good, including a discussion of just what a "trial record" is as well as the editions of this particular one. The introduction is very light on info about Joan herself. But if you are really just interested in the text, that's the translation I'd go for.
The Latin is in Pierre Champion, ed., Proces de condamnation de Jeanne d'Arc (1921).
The Latin is itself a translation from the spoken French, but the surviving French editions of the text date from much later, and scholars typically argue that the Latin is actually closer to what was originally spoken.