The Daisy Consortium offers a
free Windows app for generating ePub3 books with TTS generated SMIL audio audio overlays from epub2 books (and .html files).
I did a quick test with three French, English and German paragraphs and the generated epub3 file worked without any additional edits with
Menestrello and
Readium.
@theundeadelvis: If you find a Windows compatible Arabic TTS voice, you might be able to generate multilingual epub3 books by manually switching the TTS voice in Tobi before generating the sound file.