Not sure if this is what you ar elooking for, but I did this a few years back in VBScript. Not ideal, but it works for me:
Figure out the language:
<%
Dim sLanguage
sLanguage = Request.QueryString("lang")
Dim userLocale
userLocale=Request.ServerVariables("HTTP_ACCEPT_LANGUAGE")
Dim sDomain
sDomain = Request.ServerVariables("HTTP_HOST")
Dim languages
languages = Split(userLocale, ",", -1)
...
Set the style sheet...
<% select case MasterLanguage
case "PORTUGUESE"%>
<style media="screen" type="text/css">@import "/Includes/css/a_formatting.css";</style>
<style media="screen" type="text/css">@import "/includes/langs/br/languageSpecific.css";</style>
<link type="text/css" media="print" rel="stylesheet" href="/Includes/css/print.css" />
<%
case "SIMPCHINESE"
%>
<style media="screen" type="text/css">@import "/Includes/css/a_formatting_zh-cn.css";</style>
<style media="screen" type="text/css">@import "/includes/langs/zh-cn/languageSpecific.css";</style>
<link type="text/css" media="print" rel="stylesheet" href="/Includes/css/print_zh-cn.css" />
<%
I can post more snippets if this is helpful.