Brand new is Share to Speech, tying into Windows Phone 8.1's 'Share' system, so that you can share anything textual with it and the utility will read the text out loud, in the background if needed, while you get on with something else, either on the phone or around the house/office, or while driving. It's early days for the application, of course, and there's limited possibilities outside Office and Internet Explorer, but your comments welcome if you find other apps that work well with itl.

From the Store description (still marked as beta in my region):

Save your time by listening to articles and documents while doing something else. Also a great assistive technology for people with visual impairments and disability.

• start the speech in seconds from any app that supports sharing, including Internet explorer and Office
• a data connection is used only to download the text of the article
• 13 languages supported with auto language detection
• share to the phone using Windows 8.1 app and articles will appear automatically in short time (and will be available later even without the data connection)
• tracking of unread articles and an indicator on the live tile

Here's Share to Speech in action, on various devices (Lumia 1020 and 1520):

From any (local) Office document of (here) web page, use the Windows Phone 'Share' tool and you should see 'Share to Speech'....

There's the choice of playing immediately or adding to a playback queue, shown here (left), with the approximate audio playback times for each item; (right) while playing, there's a foreground UI, which you can interact with - or just leave it all playing in in the background while you get on with the washing up(!)

Two of the live tile options, showing just the number of items queued and (right) the opening text from the next queued piece, on the largest live tile.

There are quite a few limitations at the moment, it doesn't work with documents in OneDrive, for example, plus Share to Speech doesn't always appear in the Windows Phone 'Share' menus. And playback in the background on some devices does suffer some break-up, presumably because of Windows Phone processor/multitasking restrictions.

Still, a potentially very useful tool for the platform. You can grab Share to Speech here in the Store.

PS. There's also a promo video, which you may find of interest: