The application process must be conditional on "REQUEST contained in Expression1", where Expression1 contains a list of the accepted language identifiers, for example if the application is available in english and spanish, Expression1 must contain "en,es".

begin :FSP_LANGUAGE_PREFERENCE := :REQUEST; htp.init; owa_util.redirect_url('http://apex.oracle.com/pls/otn/f?p=' ||:APP_ID||':'||:APP_PAGE_ID||':'||:APP_SESSION); end;