Yes, you can do this. Here's how:
Note: I'm on Froyo (Android 2.2), so if you're on a different version it may be slightly different.
- Go To your home screen.
- Choose Settings from the Menu
- Choose Language & Keyboard
- Choose Android Keyboard
- Choose Input Languages
- Select the English and German Languages
- Exit out by pressing the Home Key
You're now set up for German and English.
Here's how to test it:
- Open the browser
- Tap the address bar to bring up the keyboard
- LONG PRESS the address bar (or text field, whatever you want to call it)
- Look at the the space bar: it will have the following: < English >
- Now SWIPE/SLIDE your finger over the space bar, you'll see it change to < German >
Once < German > is selected, you're now using the German keyboard.
Swipe again to return to English.