I am trying to create an EPUB3 with read-aloud on my children's book. I have tried CircularFlo and PubCoder. Both applications are able to add the read-aloud feature to the EPUB3. However, it is only supported by Apple Books and Kobo, not on Google Books.
Does anybody know the authoring tool that will allow us to add the read-aloud feature that will work for Google Books? I spoke to Google Partner Center support. They do not know which software is able to do that.