DITA-OT issue #2146

main.xsl

<?xml version="1.0" encoding="utf-8"?>

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:template match="*[contains(@class, ' topic/topic ')]">
    <xsl:message terminate="yes">
      <xsl:call-template name="getVariable">
        <xsl:with-param name="id" select="'Warning'"/>
      </xsl:call-template>
    </xsl:message>
  </xsl:template>

</xsl:stylesheet>

plugin.xml

<plugin id="my.test">
  <feature extension="dita.xsl.strings" file="strings.xml"/>
  <feature extension="dita.xsl.xhtml" file="main.xsl"/>
</plugin>

strings-en.xml

<?xml version="1.0" encoding="utf-8"?>

<strings xml:lang="en-us">
  <str name="Warning">PROCESS TERMINATED</str>
</strings>

strings.xml

<?xml version="1.0" encoding="utf-8"?>

<langlist>
  <lang xml:lang="en"     filename="strings-en.xml"/>
  <lang xml:lang="en-us"  filename="strings-en.xml"/>
</langlist>