title: angular-translate - Fallback language for determinePreferredLanguage()
body: <p>I use <a href="http://angular-translate.github.io/">angular-translate</a> in my app. How can I register a fallback language if the <code>determinePreferredLanguage()</code> returns a language key my code doesn't know?</p>
  
  <p>I want to fall back to english if someone from e.g. Sweden visits my site (language key: <strong>sv</strong>). But since I haven't listed <strong>sv</strong> in my <code>registerAvailableLanguageKeys</code> function, it fails, and the language-keys are shown to the user instead of the translation.</p>
  
  <pre class="lang-js prettyprint-override"><code>$translateProvider
      .registerAvailableLanguageKeys(['da-dk','en-us'], {
          'en_US': 'en-us',
          'en_UK': 'en-us',
          'da': 'da-dk',
      })
      .determinePreferredLanguage();
  </code></pre>