Found in this thread: http://www.chatbots.org/ai_zone/viewthread/325/#2573
The Google AJAX Language Detect API:
http://www.google.com/uds/samples/language/detect.html
It’s part of the Google Language API familly
http://code.google.com/apis/language/
I personally believe this can be used by allchatbots, just to test the language. If the language is not supported, the chatbot can always return: ‘sorry I don’t speak <language>’
In the demo below ‘welke taal is dit?’, is Dutch indeed btw.