Here's how you can change the language of labels in the Apple Maps app on your iPad, iPhone, iPod or iPad mini.
1. Go to Settings.
2. Go to Maps.
3. Toggle the Always English switch to the Off position.
4. Exit Settings.
5. Open the Maps app on your iOS device. You'll see the change if you are in an area where English is not the main language.
For more, see the original article at the link below.
How to Change the Language of Apple Maps Labels | OS X Daily