Use the Web UI language selector to override language settings. If you introduce additional languages, update the language selector to incorporate them.
<div id = "languageSelector">    
  <script type = "text/javascript"> // <![ CDATA [    
     function _switch() {    
       \ $j ( "\# languageSelector").toggle("medium");    
       return   false ;    
     }   
  //]]></script>    
  <ul id = "language-select">    
   <li>    
     <a onclick = "_switch()" wicket:id = "changeToEnglish">   
     <wicket:message key = "application.header.language.english"/>    
     </a>    
   </li>    
   <li>    
     <a onclick = "_switch()" wicket:id = "changeToGerman">    
     <wicket:message key = "application.header.language.german"/>    
     </a>    
   </li>    
 </ul>   
</div>
protected void initOwnPageComponents() {    
...    
   add(new Link("changeToEnglish") {    
     @Override    
     public void onClick() {    
       getWebSession().setLocale(getUpdatedLocale("en_US"));   
       getSession().info (    
       getLocalizer().getString("language.change.success", this));    
       setResponsePage(getApplication().getHomePage());    
    }    
   };    
   
   add(new Link("changeToGerman") {    
     @Override    
     public void onClick() {    
       getWebSession().setLocale(getUpdatedLocale("de_DE"));    
       getSession().info(getLocalizer().getString("language.change.success, this));   
       setResponsePage(getApplication().getHomePage());    
     }    
   };    
... 
}