It is good to set language in ``html`` tag.
--- a/html.rst Sun Jun 19 19:59:21 2016 +0300
+++ b/html.rst Sun Jun 19 20:01:35 2016 +0300
@@ -52,6 +52,10 @@
W3C best practice suggest to surround corresponding text pieces in tag with
``lang`` attribute. Attribute values are from BCP 47.
+It is good to set language in ``html`` tag::
+
+ <html lang="en">
+
http://www.iana.org/assignments/language-subtag-registry/language-subtag-registry
IANA registered language and country codes. Coherent with ISO codes but
frequently updates.