What kind of decryption is used in this example?
Well, it seems it is a basic substitution cipher, with a twist: some letters map to the same cipher text letter (not just e,r,t map to l, also e.g. n,u map to o . So decryption is not unique. But a pattern matching algorithm with a German dictionary could probably filter those. The mapping seems to group letters in such a way, that only one combination makes sense.

Anyway, from the example text you can probably find most character mappings, and then you just need to guess words based on valid combinations in a dictionary.

In general, I would not actually call this encryption at all. A scheme like this won't work for just any non-injective mapping, so it's unclear if there is some key involved or not. Also, an encryption scheme requires, that (with overwhelming probability) the decryption is unique and correct, s.t. $D(E(m))=m$.