I know you shouldn't ask two questions at once as you'll probably get the answer to the one less important but here goes.
1) In a Nuvi 255w, can I sanitize the Voice directory and get rid of Ancient Aramaic, Middle Kingdom hieroglyphic (modern) etc. to save space and just keep the language I am interested in? I assume that will speed it up and also free up oodles of space.
2) According to what ...