diff --git a/_includes/header.html b/_includes/header.html
index 53bc05a..a4801f2 100644
--- a/_includes/header.html
+++ b/_includes/header.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html class="no-js" lang="">
+<html class="no-js" lang="en-US">
 
 <head>
   <meta charset="utf-8">
@@ -9,4 +9,4 @@
   <link rel="stylesheet" href="{{ site.baseurl }}/assets/css/style.css">
 </head>
 
-<body>
\ No newline at end of file
+<body>
