Re: global language parameter

I think others here have certainly set you on the right XSLT track,
and A. Welch's recomendation about CSS is good advice. That said, it
is worth considering if XSLT is the right place to do this work. 

My instinct, which others may convince me is wrong, is to just
transform the xml:lang= in the TEI input into lang= in the XHTML
output, and ask CSS to do all the heavy lifting.

I.e., I would likely use something like

  <xsl:template match="@xml:id">
    <xsl:attribute name="lang">
      <xsl:value-of select="@xml:id"/>
    </xsl:attribute>
  </xsl:template>

in my XSLT, and then something like

 :lang(sa) { font-family: 'Times Ext Roman'; }
 :lang(zh) { font-family: Mincho, MingLiU, Batang, Simsun; }
 :lang(ko) { font-family: Batang, BatangChe; }

in my CSS.