diff --git a/common/dtd/ldml.dtd b/common/dtd/ldml.dtd
index 2b506607c48..efe1565f53d 100644
--- a/common/dtd/ldml.dtd
+++ b/common/dtd/ldml.dtd
@@ -63,7 +63,7 @@ CLDR data files are interpreted according to the LDML specification (http://unic
 <!ATTLIST language type NMTOKEN #REQUIRED >
     <!--@MATCH:validity/locale-->
 <!ATTLIST language alt NMTOKENS #IMPLIED >
-    <!--@MATCH:literal/long, secondary, short, variant, menu-->
+    <!--@MATCH:literal/long, secondary, short, variant, menu, official-->
 <!ATTLIST language draft (approved | contributed | provisional | unconfirmed | true | false) #IMPLIED >
     <!--@METADATA-->
     <!--@DEPRECATED:true, false-->
diff --git a/common/main/en.xml b/common/main/en.xml
index f06eb8c889a..0f75e2c1de3 100644
--- a/common/main/en.xml
+++ b/common/main/en.xml
@@ -426,6 +426,8 @@ annotations.
 			<language type="mua">Mundang</language>
 			<language type="mul">Multiple languages</language>
 			<language type="mus">Muscogee</language>
+			<language type="mus" alt="variant">Muscogee</language>
+			<language type="mus" alt="official">Mvskoke</language>
 			<language type="mwl">Mirandese</language>
 			<language type="mwr">Marwari</language>
 			<language type="mwv">Mentawai</language>