How to let users select a language and locale themselves?

Question

Admin can change the locale for the whole site. The question is, is it possible to let end users do it themselves? Something like a language switcher at the right top corner of a page with a few languages to choose from?

Comments

It's not possible yet, and I haven't seen a plugin so far.

Answer 1

I hacked core and realized it on my site.

Extra Userfield:
http://www.question2answer.org/qa/22728
Step1: Add "language" field of selection-box[drop-down] type.
Step2: Input lines to "Extra Settings" below.

@EVAL

require_once QA_INCLUDE_DIR.'qa-app-admin.php';

$options = qa_admin_language_options();

$extstr = '';

$next = false;

foreach($options as $key=>$option) {

  if($next) $extstr .= '||';

  $extstr .= $option . '==' . $key;

  $next = true;

}

return $extstr;

+

Core hack (add lines below):
qa-inclde/qa-base.php (L1024 [case V1.6.2])

// add [start]

$userid = qa_get_logged_in_userid();

if(isset($userid)) {

  if(!isset($_SESSION['qa_session_userlang'])) {

    $userprofile = qa_db_select_with_pending(qa_db_user_profile_selectspec($userid, true));

    if(array_key_exists('language', $userprofile))

      $_SESSION['qa_session_userlang'] = $userprofile['language'];

    else

      $_SESSION['qa_session_userlang'] = $languagecode;

  }

  $languagecode = $_SESSION['qa_session_userlang'];

}

// add [end]

Our users who registered can choose favorite language, but there is some issue in this hack. For example, email is sent to another user by the language that user chose. You may solve this issue by judging $identifier parameter of qa_lang() function.