If you want to use a non-English interface you would install the langpack for example <a href="https:&#x2F;&#x2F;ftp.mozilla.org&#x2F;pub&#x2F;firefox&#x2F;releases&#x2F;44.0&#x2F;win32&#x2F;xpi&#x2F;" rel="nofollow">https:&#x2F;&#x2F;ftp.mozilla.org&#x2F;pub&#x2F;firefox&#x2F;releases&#x2F;44.0&#x2F;win32&#x2F;xpi&#x2F;</a> you would need to navigate the ftp to match your particular install.