diff --git a/default_environment/templates/html/main.dust b/default_environment/templates/html/main.dust
index 62e6748..3e96a21 100644
--- a/default_environment/templates/html/main.dust
+++ b/default_environment/templates/html/main.dust
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
   <head>
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
