It doesn't seem to work I can't even See where there are more than three voices available. When I highlight text on different types of web pages and try different ways to have it read aloud it is still not working.
@andrew84: It's a mess because the company doesn't have a strategy, they don't know who they're making the browser for and why. They have underdeveloped games in the form of Crypto, GX, Air, Neon, and apparently there is no limit to this idiocy, as a result, bugs on a normal browser are not fixed, and they even have a leaky 135 on their Dev channel, when 138 is already stable for other developers.