documentation is also an array, and lang is optional thanks @ahocevar for the catch

Author: Bart van den Eijnden

lib/OpenLayers/Format/WFSDescribeFeatureType.js

@@ -156,11 +156,13 @@ OpenLayers.Format.WFSDescribeFeatureType = OpenLayers.Class(
             },
             "documentation": function(node, obj) {
                 if (!obj.documentation) {
-                    obj.documentation = {};
+                    obj.documentation = [];
                 }
-                var lang = node.getAttribute("xml:lang");
                 var value = this.getChildValue(node);
-                obj.documentation[lang] = value.replace(this.regExes.trimSpace, "");
+                obj.documentation.push({
+                    lang: node.getAttribute("xml:lang"),
+                    textContent: value.replace(this.regExes.trimSpace, "")
+                });
             },
             "simpleType": function(node, obj) {
                 this.readChildNodes(node, obj);

tests/Format/WFSDescribeFeatureType.html

@@ -426,7 +426,7 @@
         var res = format.read(text);
         var property = res.featureTypes[0].properties[0];
         t.eq(property.annotation.appinfo[0], '{"title":{"en":"Population"}}', "appinfo read correctly");
-        t.eq(property.annotation.documentation["en"], "Number of persons living in the state", "documentation read correctly");
+        t.eq(property.annotation.documentation[0], {lang: "en", textContent: 'Number of persons living in the state'}, "documentation read correctly");
     }
 
     </script>