3166.
 @@
 
+@RET@          FcBool
+@FUNC@         FcLangSetDel
+@TYPE1@                FcLangSet *                     @ARG1@          ls
+@TYPE2@                const FcChar8 *                 @ARG2@          lang
+@PURPOSE@      remove a language from a langset
+@DESC@
+<parameter>lang</parameter> is removed from <parameter>ls</parameter>.
+<parameter>lang</parameter> should be of the form Ll-Tt where Ll is a
+two or three letter language from ISO 639 and Tt is a territory from ISO
+3166.
+@@
+
+@RET@          FcLangSet *
+@FUNC@         FcLangSetUnion
+@TYPE1@                const FcLangSet *               @ARG1@          ls_a
+@TYPE2@                const FcLangSet *               @ARG2@          ls_b
+@PURPOSE@      Add langsets
+@DESC@
+Returns a set including only those languages found in either <parameter>ls_a</parameter> or <parameter>ls_b</parameter>.
+@@
+
+@RET@          FcLangSet *
+@FUNC@         FcLangSetSubtract
+@TYPE1@                const FcLangSet *               @ARG1@          ls_a
+@TYPE2@                const FcLangSet *               @ARG2@          ls_b
+@PURPOSE@      Subtract langsets
+@DESC@
+Returns a set including only those languages found in <parameter>ls_a</parameter> but not <parameter>ls_b</parameter>.
+@@
+
 @RET@          FcLangResult
 @FUNC@         FcLangSetCompare
 @TYPE1@                const FcLangSet *               @ARG1@          ls_a
 
   <refsect2><title><literal><charset></literal></title><para>
 This element holds at least one <literal><int></literal> element of
 an Unicode code point or more.
+  </para></refsect2>
+  <refsect2><title><literal><langset></literal></title><para>
+This element holds at least one <literal><string></literal> element of
+a RFC-3066-style languages or more.
   </para></refsect2>
   <refsect2><title><literal><name></literal></title><para>
 Holds a property name.  Evaluates to the first value from the property of