UIReturnKeyType: different colors, and languages information

I recently was trying out different return keys (UIReturnKeyType) for the default keyboard in iOS 7, looking for a fitting text to display for calculating taxi fares from one location to another. Since the app is for the German market, I needed to find out the text translations in German. Unfortunately, I couldn’t find the translations anywhere, so I had to try out the different variations myself and see what translation appeared. In doing so I also noticed (or rather, my boss noticed) that the different return key styles don’t all have the same color. And of course, neither the texts nor the colors can be individually chosen. I decided to make some screenshots and collect details about the different texts and colors.

UIReturnKeyType English text German text
UIReturnKeyDefault Return Return
UIReturnKeyGo Go Öffnen
UIReturnKeyGoogle Search Suchen
UIReturnKeyJoin Join Verbinden
UIReturnKeyNext Next Weiter
UIReturnKeyRoute Route Route
UIReturnKeySearch Search Suchen
UIReturnKeySend Send Senden
UIReturnKeyYahoo Search Suchen
UIReturnKeyDone Done Fertig
UIReturnKeyEmergencyCall Emergency Call Notruf

All of the button types are greyed out (with a grey text label) when no text has been entered.

 

When text has been entered, all buttons except for UIReturnKeyDefault and UIReturnKeyNext become blue (with a white text label).

Both UIReturnKeyDefault and UIReturnKeyNext are grey with a black text label when text has been entered.