If you use Chrome on Android, there is a "Listen to this page" option in the menu.

https://support.google.com/chrome/answer/14768725?hl=en

Doesn't actually read the page, though. Or not what you see in the browser. For example right now, when I navigate to "reply" it doesn't read the comment I'm replying to - it's reading the login banner you get visiting a reply link without being logged in.