function Add_user_fields($user) {
echo '<table class="form-table">
    <tr>
        <th><label for="dropdown">Sprache/Lingua</label></th>
        <td>';

$selected = get_the_author_meta('user_lang', $user->ID);

echo '<select name="user_lang" id="user_lang">
      <option value="de_DE" ';
      if($selected == "de_DE") { echo 'selected="selected"'; }
      echo '>Deutsch</option>
      <option value="it_IT" ';
      if($selected == "it_IT") { echo 'selected="selected"'; }
      echo '>Italiano</option>

</select>
        </td>
    </tr>
</table>';
}

add_action('personal_options_update', 'save_user_fields');
add_action('edit_user_profile_update', 'save_user_fields');

function save_user_fields($user_id) {

if (!current_user_can('edit_user', $user_id ))
    return false;

//save dropdown
update_usermeta($user_id, 'user_lang', $_POST['user_lang']);
}