Trying to tell a story without dialogue

I picked up a 5.5 x 8.5 inch spiral bound sketch pad in town last night that I am using to make a storyboard book for a 3D film I want to create. The trouble is, I want to tell the story without speech, since I don't have any voice actors, and I am learning that it is harder than one might expect to draft a silent film. I suppose it would be easier if I went with the silent film style where cards between scenes describe what was said, however, I want to try to make it so that the images all speak for themselves, and that is not as easy as I would hope when I want to tell a fantasy saga style story.

I'm either going to have to cave and do a less epic story, or figure out how to do the voices. Think I will try testing out changing my own voice using Audacity's various tools for changing tone and pitch and stuff, see what I can come up with there. Thankfully the story only has a couple of male characters, so maybe I can fake my way through it with voice changing software.