How to use vocie commands for sending text and email on my Galaxy tablet

I have a Galaxy tablet running Andriod 2.2 and I have wacthed the tutorial video numberous times on how to speak a command for sending text's and emails. The problems is when I say " send text to Brent Armstrong" and then the message, it doesn't associate the name. The window it displays back to me has the tilte "Text message" at the top, then the "To:" line is blank and then in the meassage field it shows "to Brent Armstrong" with the remainder of my meassage. I'm guessing I have to associate a wave file with each on my contacts, but not sure....confused because my other devices are the IPad and IPhone so this is my first exposure to Andriod.