Thats why I based it on a version before python-Levenshtein was even added to the project. The Levensthein part is just the normal levenshtein stuff that is a standard task at university I suppose, so it was definetly faster to implement this on my own instead of reading ugly C code. From my tests it is about as fast as the one used by python-Levenshtein (a little bit slower), but therefore I can read it ...