diff --git a/README.md b/README.md
index bbee0f9..7eb4114 100644
--- a/README.md
+++ b/README.md
@@ -464,6 +464,6 @@ Example qqq.json:
 ```
 
 In MediaWiki and its hundreds of extensions, message documentation is a strictly followed practice. There is a grunt task to check whether all messages are documented or not. See https://www.npmjs.org/package/grunt-banana-checker
-
+This is my first contribution.
 [npm]: https://img.shields.io/npm/v/@wikimedia/jquery.i18n.svg
 [npm-url]: https://npmjs.com/package/@wikimedia/jquery.i18n
diff --git a/src/jquery.i18n.messagestore.js b/src/jquery.i18n.messagestore.js
index ba81ce5..99b1ba0 100644
--- a/src/jquery.i18n.messagestore.js
+++ b/src/jquery.i18n.messagestore.js
@@ -100,13 +100,15 @@
 		 * @param {string} locale
 		 * @param {Object} messages
 		 */
-		set: function ( locale, messages ) {
-			if ( !this.messages[ locale ] ) {
-				this.messages[ locale ] = messages;
-			} else {
-				this.messages[ locale ] = $.extend( this.messages[ locale ], messages );
-			}
-		},
+	 set: function ( locale, messages ) {
+	var clonedMessages = $.extend( true, {}, messages );
+
+	if ( !this.messages[ locale ] ) {
+		this.messages[ locale ] = clonedMessages;
+	} else {
+		this.messages[ locale ] = $.extend( true, {}, this.messages[ locale ], clonedMessages );
+	}
+},
 
 		/**
 		 *