i18n: Clients can elect a language preference

include/class.client.php

@@ -375,6 +375,10 @@ class ClientAccount extends UserAccount {
 
         $this->set('timezone_id', $vars['timezone_id']);
         $this->set('dst', isset($vars['dst']) ? 1 : 0);
+        // Change language
+        $this->set('lang', $vars['lang'] ?: null);
+        $_SESSION['client:lang'] = null;
+        TextDomain::configureForUser($this);
 
         if ($vars['backend']) {
             $this->set('backend', $vars['backend']);

include/client/profile.inc.php

@@ -48,6 +48,24 @@ if ($acct = $thisclient->getAccount()) {
             <strong><?php echo Format::date($cfg->getDateTimeFormat(),Misc::gmtime(),$info['tz_offset'],$info['dst']); ?></strong>)</em>
     </td>
 </tr>
+    <tr>
+        <td width="180">
+            <?php echo __('Preferred Language'); ?>:
+        </td>
+        <td>
+    <?php
+    $langs = Internationalization::availableLanguages(); ?>
+            <select name="lang">
+                <option value="">&mdash; <?php echo __('Use Browser Preference'); ?> &mdash;</option>
+<?php foreach($langs as $l) {
+$selected = ($info['lang'] == $l['code']) ? 'selected="selected"' : ''; ?>
+                <option value="<?php echo $l['code']; ?>" <?php echo $selected;
+                    ?>><?php echo Internationalization::getLanguageDescription($l['code']); ?></option>
+<?php } ?>
+            </select>
+            <span class="error">&nbsp;<?php echo $errors['lang']; ?></span>
+        </td>
+    </tr>
 <?php if ($acct->isPasswdResetEnabled()) { ?>
 <tr>
     <td colspan=2">