Why couldn't Vista understood my "dog"?

I spent some time to try out the speech recognition and text-speech feature of Windows Vista (and also Microsoft Office 2007), and I found out that:

- Among all Microsoft Office 2007 applications, only Excel can support text to speech feaure. I mean, WHY? Why not Microsoft Word?

- The Vista speech recognition kept failing to recognize my word "dog", and I still don't know whether I should blame Microsoft or my accent.

- The voice recognition ability is far from practical for daily life. It's a nice gimmick though, and it gives me one more thing to show off when I am in front of a Vista computer.

Also, something totally UNRELATED: I have problem downloading the Circuit City email to my thunderbird off line email repository. Maybe later I need sometime to sort this thing out.