To ensure correct pronunciation, screen readers use a different sound library for each language they support. Screen readers can switch between these language libraries easily, but only if a web page specifies which language to read for a given piece of content.
To ensure correct pronunciation of the page as a whole,
you must specify a valid
BCP 47 language
How the Lighthouse invalid
lang value audit fails
flags pages whose
<html> element doesn't have a valid value
Note that the
<html> element does not have a
[lang] attribute audit
checks whether a
lang attribute is present.
This audit checks whether the value for that attribute is valid.
The Lighthouse Accessibility score is a weighted average of all the accessibility audits. See the Lighthouse accessibility scoring post for more information.
How to fix an invalid HTML
To ensure your page's content is pronounced correctly for screen reader users,
use a valid language code
lang attribute of the
For example, this sample code sets the language of the document to English:
- Source code for
<html>element does not have a valid value for its
- <html> element must have a valid value for the lang attribute (Deque University)