Text to Speech - Word

I have Office 2007 right now, with Vista. When I try to use the Microsoft
Narrator with a Word document, it reads the information about the Word
document (title, etc.), but when I try to get it to read the text in the
document, it says it's a blank page. I haven't been able to find any help to
get this to work. I work in disability services and our students with Windows
XP and Office 2003 use the language bar to read their documents out loud, and
I'm just trying to find out how to get the same results for students with
Vista and Office 2007.