Supersite for Windows posted Windows Phone 8.1 Tip: Configure a Voice Navigation App
A quote from the article:
Windows Phone 8.1 ships with a basic Maps app, which provides location and direction information, as well as a neighborhood guide called Local Scout. What's missing, of course, is voice guided turn-by-turn navigation. But thanks to an integration model, these facilities can be provided by a third party app that you can get from your handset maker, your wireless carrier, or the Store. Here's how to configure a navigation app, and access it from Maps.Windows Phone 8.1 Tip: Configure a Voice Navigation App @ WinSupersite