Yes it is as I have developed voice recognition system using the 8052,which can recognise single words at a fairly high accuracy.A disabled friend of mine uses it to control domestic appliences by voice control.
How you do it,orhow I did it rather was to take some ideas from image recognition and apply them to sound samples.
I havent done much work on it for some time but I can give you some pointers to get you started if you mail me its a bit too long winded to go into in detail here.My new email address is jc.smith19@btopenworld.com