I tried to test it with file names other than english.xml, but it didn't seem to recognize anything other than english.xml. English.pak only contains english.xml and "language.lsx" which looks like this:

<?xml version="1.0" encoding="UTF-8" ?>
<save>
<header version="2" time="1367571612" />
<version major="1" minor="3" revision="0" build="0" />
<region id="Config">
<node id="root">
<children>
<node id="ConfigEntry">
<attribute id="MapKey" value="Language" type="22" />
<attribute id="Type" value="1" type="5" />
<attribute id="Value" value="English" type="20" />
</node>
</children>
</node>
</region>
</save>

Epic Encounters, gameplay overhaul and content expansion