While there is a text-to-speech engine (flite) available, what you want is the other way around ... a speech recognition app. I have not heard of one for the N800. Unfortunately, I would suspect that there won't be since speech recognition is pretty CPU intensive and the N800 isn't a huge number cruncher. You never know though. Someone might find an efficient enough algorithm that matches the capability of the N800 so I would never say never.