In Windows (8.1 and other windows versions) one as several possibilities:
1 - ebook readers
One of them (app in windows 8.1 / 10) is Book Bazar Reader, can read several formats inclusive mobi and epub and has TTS.
Best of all the free version is fully functional.
2 - Programs that “read to us”
Textaloud -
http://nextup.com/TextAloud/
Not free. It’s a very good program and also one can buy voices from them.
If buying voices, my advice is to choose Ivona ones, they are exceptional (as other people have told before).
Balabolka -
http://cross-plus-a.com/balabolka.htm
Free - there is also a portable version in their website or from
http://portableapps.com.
As long as I can see it’s very similar to Textaloud, very light and can open all the normal text, doc and eBook formats (mobi, epub, etc.)
Both permit the creation of audiobooks - saving in wav / mp3 the read text, thus hearing it in any audio device one desires.
Best regards,