That does not seem to work in this situation. Do I need to define the data type of the sequence? 

   <xsl:template mode="mb" match="*[contains(@language, 'multi-byte')]">
        <xsl:value-of select="count(tokenize(lower-case(.),'(\s|[,.!:;]|[$][n][b][s][p][;])+')[string(.)])"/>
      </xsl:template>  
 
      <xsl:variable name="mb">
           <xsl:apply-templates mode="mb"/>
       </xsl:variable>  

        <xsl:variable name="mbt" select="sum(for $n in number($mb) return number($n))"/>

Karen