No, they don't talk, besides uttering some very few words..
The only Ds game I can remember seeing having any speech at all is "Elite Beat Agents" From the trailers (I haven't played it yet..
) he seems to shout "Agents GO!" but apart from some very few words, the ds games have no speech..
Just finished phoenix wright by the way.. Wow!
Can't wait for the next one. I'll have to get hold of touch detective (yes, I have heard the fishy reviews, but I want to try it regardless) and Elite Beat Agents to shorten the wait..