diff --git a/public/404.html b/public/404.html
index 85c2bb31..c2d36575 100644
--- a/public/404.html
+++ b/public/404.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
 <head>
   <meta charset="utf-8">
   <title>Page not found</title>
diff --git a/public/500.html b/public/500.html
index a3c891b6..47e8aaa2 100644
--- a/public/500.html
+++ b/public/500.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
 <head>
   <meta charset="utf-8">
   <title>Error</title>
diff --git a/views/app.erb b/views/app.erb
index adc1b2af..3db4f665 100644
--- a/views/app.erb
+++ b/views/app.erb
@@ -3,7 +3,7 @@
     <a class="_home-link"></a>
     <a class="_menu-link"></a>
     <form class="_search">
-      <input type="search" class="_search-input" placeholder="Search&hellip;" autocomplete="off" autocapitalize="off" autocorrect="off" spellcheck="false" maxlength="30">
+      <input type="search" class="_search-input" placeholder="Search&hellip;" autocomplete="off" autocapitalize="off" autocorrect="off" spellcheck="false" maxlength="30" aria-label="Search">
       <a class="_search-clear"></a>
       <div class="_search-tag"></div>
     </form>
diff --git a/views/index.erb b/views/index.erb
index 22fba99e..3bd5f860 100644
--- a/views/index.erb
+++ b/views/index.erb
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html<%= ' manifest="/manifest.appcache"' if App.production? %> prefix="og: http://ogp.me/ns#">
+<html<%= ' manifest="/manifest.appcache"' if App.production? %> prefix="og: http://ogp.me/ns#" lang="en">
 <head>
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no,shrink-to-fit=no">
diff --git a/views/other.erb b/views/other.erb
index e8bcdc45..63beb26d 100644
--- a/views/other.erb
+++ b/views/other.erb
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
 <head>
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
