From the Google forum:
1:02 PM (4 hours ago)
Thanks for reporting your issue with release 6.6.
Our team is working to investigate this issue. Please answer the following question if possible:
1. Where is there locale on your phone. Go into Google Maps>Menu>Settings>About and look at your Locale. (i.e. en_US) and tell us what that says.
2. Please check that text-to-speech is working on your phone. You can do so by checking if an app like Google Translate (which they can download from Google Play) can playback text or by going to Settings > Language & input > Text-to-speech output > Listen to an example.
3. Also are you experiencing this issue in all areas? Or just in areas where you have poor network/data connection?
5. Lastly if you have not done so, please let us know what version your on for Android (i.e. 4.0.2, 4.0.4, etc).
Thanks! This information will help us investigate what's going on, and thanks for your patience. Once I get some responses, I'll report back to the team and provide updates as soon as they are available.