Themes/default/index.template.php
查找：
// If the user is logged in, display stuff like their name, new messages, etc.
找到后在这部分里
<td colspan="2" width="100%" valign="top" class="windowbg2"><span class="middletext">';
// If the user is logged in, display stuff like their name, new messages, etc.
if ($context['user']['is_logged'])
在<span class="middletext">前添加
<div style="float:right;font-size:11px;"><a href="', $scripturl, '?language=english;topic=' . $context['current_topic'] . '">English</a><br /><a href="', $scripturl, '?language=chinese_simplified_utf8;topic=' . $context['current_topic'] . '">简体中文</a><br /><a href="', $scripturl, '?language=chinese-traditional-utf8;topic=' . $context['current_topic'] . '">繁體中文</a></div>
Simple Machines的切换代码
<div id="lng_select"><form action="http://www.smf.cn/bbs/index.php" method="post" class="smalltext" style="float: right;">
<label for="language_select" class="smalltext">界面语言:</label> <select id="language_select" name="language" onchange="this.form.submit()" class="smalltext">
<option value="chinese_simplified_utf8" selected="selected">简体中文</option>
<option value="chinese-traditional-utf8">繁體中文</option>
<option value="english">English</option>
</select> <noscript><input type="submit" value="Go" /></noscript>
</form></div>
