For a start, I agree with IFW that voice recognition is pure software. A month ago, I developed a voice mail system for my company. This is based in voice recognition and so far the tests have been going well. It's all about proper programming actually and I won't use the voice recognition of Mac or MS or whatever as an example about Voice Recognition being crap.
A correction to IFW though. The DS has TWO CPUs, an Arm7 and an Arm9. You can easily dedicate the Arm9 to the gaming and the Arm7 on other tasks. Considering that Nintendo has been good in providing the necessary APIs to developers, 'playing' with the two CPUs can be a joy. Although the PSP has powerful hardware, I am not sure whether it matters that the DS will have less polygons than the PS when you view a screen so small that you can hardly see the difference.
My perception about handhelds is not to provide the best hardware but the best support. This is where Nintendo has an advantage in my opinion. Also, Nintendo has always designing hardware with the rest of their systems in mind. The DS will also play GBA games which is great.
Regarding the target audience, they both target to the same market. Even if the case is for Nintendo to target the kids' market and the Sony the adult market, this is a pure suicide for Sony. I am not sure how many 18+ year old people would like a huge device just to play games in the bus, the train and so on. People are more interested in other things after a point, unless you expect a 40 year old man taking out a PSP and playing games while sitting beside his wife and kids (who apparently will have a DS
). If Sony targets this market, the PSP is dead already but I doubt the target market is this. They both are targeting the same market. If they were not, they wouldn't feel so antagonistic already. After all, I see nothing that makes the PS2 more adult than the Gamecube or the N64. I've see both kids and adults using them.