Have the OS speak the selected text from Word. This is a system service in most Mac apps, but not in Office.

say-Word-selection.applescript

tell application "Microsoft Word"
  activate
	tell selection
		set myText to content of text object
	end tell
end tell

tell application "System Events"
	-- Fork it to another process so it doesn't prevent you from doing other stuff in the foreground in Word
	do shell script "echo " & myText & " | say > /dev/null 2>&1 &"
end tell