Greetings,
I've looked at the website and the problem seems to be that you don't actually have an input with a value for the selected language, there are only 'submit' type inputs, so no data gets sent as POST parameters.
Is the language changing mechanism implemented on the server side? If so, what is the request path and what are the parameters that it needs in order for the request to be successful?
With kind regards,
Lucian