<p>I need to write a module to detect similar documents. I have read many papers of fingerprints of documents techniques and others, but I do not know how to write code or implement such a solution. The algorithm should work for Chinese, Japanese, English and German language or be language independent. How can I accomplish this?</p>

You can use or at last study
difflib
from Python's stdlib to write your code.
It is very flexible, and has algorithms to find differences between lists of strings, and to point these differences. Then you can use the
```
get_close_matches()
```
to find similar words:
```
```
>>> get_close_matches('appel', ['ape', 'apple', 'peach', 'puppy'])
['apple', 'ape']
```
```
It is not the solution but maybe it is a start.