I was talking about this with Léonie just yesterday. I, for one, would love to have CSS speech support. You know who else would love it? Content designers!
In these days of voice interaction on every platform, there is a growing expectation that it should be possible to design that experience just like we can the visual experience. In the same way an organisation chooses a logo and colour palette for its website, it stands to reason that they may also choose a particular voice that represents their brand.
It’s wild that there’s no way to do this on the web.