This script is very easy to install. It is optimized right now, for the German and English languages.
Features front-end: extra information about plural forms, extra keys for special German characters, weekly statistics using a cronjob possible. Admin receives an info email each week. Built-in possibility for Google ads.
Features back-end: data entry form, auto fill of the plural input field if a German noun is typed into the singular field, dublicate control of vocab, statistics page about the number of words and queries.