It will do both SAPI5 voices and onlines voices from a number of sources. If you go to "Tools" then online services, you get another window that has a number of online sites. You type in the text, hit save and wait for the online TTS to finish. Some of these are very good.
With SAPI5 you have to mess around with window control panel and enable multiple languages, but some of the later M$ voices are a lot better than the old ones.