What's in a Nano that isn't in a Classic

[Larry Wanger]

We may or may not be able to answer this but I'm curious what is in  
the Nano that isn't in the classic that allows the Nano to do speech  
output? It would seem that both have similar processing and ability as  
they both play video I believe. Yet, several features in the Nano  
aren't on the Classic. I'm mainly interested in why the classic can't  
offer the speech option. I have a huge music collection and the idea  
of taking what I want down to 16GB just doesn't work for me.