Help with setting Cookies

I am trying to create a splash page (I know not the best, but my friend wants it) where you can pick which language to visit the site.

English
Dutch
French
German

I would like when they click a language that when they go off the site when they come back it remembers which language they pick.

I have tried a plugin that has helped a bit to get started, but I am not sure how to set a cookie for each language. Here is where I am at:

<?php get_header(); ?>
<SCRIPT LANGUAGE="JavaScript">
   <!-- hide from old browsers
   function setCookie(name, value, expires, path, domain, secure) {
      document.cookie = name + "=" + escape(value) +
      ((expires) ? "; expires=" + expires.toGMTString() : "") +
      ((path) ? "; path=" + path : "") +
      ((domain) ? "; domain=" + domain : "") +
      ((secure) ? "; secure" : "");
   }
   function setsplash() {
      setCookie("splash", "1", "", "/");
   }
//-->
</SCRIPT>

<div id="splash">
	<div class="splash content">
	<div class="splash enter">
		<ul>
		<li class="en"><a onclick="setsplash()" href="" title="English">English</a></li>
		<li class="nl"><a onclick="setsplash()" href="https://b-e-m.org/nl/" title="Nederlands">Nederlands</a></li>
		<li class="fr"><a onclick="setsplash()" href="https://b-e-m.org/fr/" title="Fran?ais">Fran?ais</a></li>
		<li class="de"><a onclick="setsplash()" href="https://b-e-m.org/de/" title="Deutsch">Deutsch</li>
		</ul>

</div>
</div>
</div>

<?php get_footer(); ?>

Any help with my lack of php ??