Speech recognition is already available using Personal Assistant. You can either download the demo version of PA Directory Dialer 1.1 which works only with CallManager 3.0(9) or later.
If you are using CM3.1 then you have to wait for PA Directory Dialer 1.2 demo version which will be available sometime in the next month give or take.
Also, you can purchase the full blown version of PA 1.2 in the Cisco Marketplace.