Specify user locale in Javascript tracker

I use the Javascript tracker like this:

<script type="text/javascript">
  var _paq = _paq || [];
  _paq.push(['trackPageView', '<?= $view ?>']);
  (function() {
	var u=(("https:" == document.location.protocol) ? "https" : "http") + "://";
	_paq.push(['setTrackerUrl', u+'piwik.php']);
	_paq.push(['setSiteId', 1]);
	var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.type='text/javascript';
	g.defer=true; g.async=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);

My users can change the language, I would like to “override” the Piwik report locale by this value, how can I do that?

can you try:

_paq.push('appendToTrackingUrl', 'lang=de')

is it working?