Judging from the vague wording in Microsoft's EULA, I would say, "no".
Below is a snippet where I bolded my basic interpretation of the meaning:
8. SCOPE OF LICENSE.
The software is licensed, not sold. This agreement only gives you some
rights to use the software. Microsoft reserves all other rights. Unless applicable law gives you
more rights despite this limitation, you may use the software only as expressly permitted in this
agreement. In doing so, you must comply with any technical limitations in the software that only
allow you to use it in certain ways. For more information, see
http://www.microsoft.com/licensing/userights.
There are several other statements restricting the user(s) from commercial use, but nothing really specifies the usage of the voices. Though, I'd assume they fall into the same general category as the majority of Microsoft's EULA.