Interlaguage a few reflections

Interlanguage is relevant when we have more than one language. If we take me as an example:
I have a native language(Danish) and two foreign languages(English and German). This combination means that I have two different interlaguages, one for each foreign language that I am trying to learn.
So what is an interlaguage?
An interlaguage is a stop on the road to learning a different language than your native one. It will consist of both elements from your first language and elements from second, third etc. language. This means that my German will have contradictory elements from both English and Danish. I have even picked up a little Dutch which will also serve to further confuse me when trying to speak German, or English for that matter.
It is important to understand that these different languages will not just stand in the way of each other, but also serve to help me. I might have learned something from English that will enable me to understand the way German grammar works, or my German will help my English vocabulary.
The way I understand interlaguage is that it serves to tell me, or a teacher how far I have come toward my target language. It will show what kind of errors I usually make when I speak or write and by that I will know where my other language serves to help me or put obstacles in my way.

To end this:
Try to read this and figure out what kind of error I make. I you see any, apart from typos feel free to comment and help me on my way.