I noticed that the software teaches to press the Alt Gr key with the right ring finger. I noticed that it is not really comfortable doing it that way. I find that it is more logic to use the right thumb, which is actually closer to the key and which is usually free (because you also have the other thumb to press the space bar). I don't know if you can change it, because maybe the 10 finger system is copyrighted (sorry for my bad english), but I just wanted to know what you think about it.

Thank you very much for your message. And sorry for the delay.
I think you are right, using the thumb for some keys would be better and faster. The problem is, I think there is no general "copyright", but the software is used by a lot of schools. And I think everywhere you can read that the thumb is only used for the space bar. So we could change it, but I think we would then get a lot of feedback from schools.

So feel free to use your own "system" - we can also recommend alternative keyboard layouts like NEO or Dvorak (also supported by Tipp10), where all keys are completely reordered to give you the possibility to write very fast and comfortable. If you are interested, you will find a lot of information about it on Wikipedia:
http://en.wikipedia.org/wiki/Keyboard_layout

All the best from Berlin,
your Tipp10 team