title: symfony default locale language
body: <p>i am trying for three hours change language at my website. </p>
  
  <p>I am using version 2.1.7 and i found some articles  that from version 2.0 locale was accesible via session. But now is via request.</p>
  
  <p>So i found at documentation this:</p>
  
  <pre><code>        $request=$this-&gt;getRequest();
          $locale=$request-&gt;getLocale();
  
          echo $locale;
  </code></pre>
  
  <p>Ok .. that works ... but i see 'en' which is default value in parameters.yml ... i have file messages.en.yml ... works ok. </p>
  
  <p>But when i try: (where $localExtension ='fr' ... with existing messages.fr.yml file..)</p>
  
  <pre><code>     public function changeLanguageAction($localExtension) 
  {
          $request=$this-&gt;getRequest();
          echo $localExtension;
          $request-&gt;setLocale($localExtension);
  
          return $this-&gt;redirect($request-&gt;headers-&gt;get('referer'));
  }
  </code></pre>
  
  <p>And after redirect i still see 'en' ... whats wrong? :/</p>
  
  <p>Or how can i setLocale for everypage not only at one ... </p>