It looks like the answer is: No.
The "text-to-speech" capabilities, as well as the speech recognition capabilities, have been known as the "Speech Application Programming/Programmer's Interface", abbreviated "Speech API", or "SAPI". According to Wikipedia's article on Microsoft Speech API: section on API 5.4, the version bundled with Windows 7 is SAPI 5.4. There does not appear to be a new version available for download, except that you can currently download an upgrade to the entire operating system (to upgrade to Windows 10). Even then, a quick look suggests that Windows 10 does not offer anything new in the form of the SAPI interface. People are mentioning that there is nothing new there. Microsoft's ongoing research into speech technology has been getting invested in the product they call Cortana, which is a free part of Windows 10.
The major competing speech engine, that I'm aware of, is one made by Dragon software. (It is not a free product.) At one point, Apple licensed some technology behind Dragon software in order to make Siri.