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.
If the language changes within your page, you must specify a valid BCP 47 language to ensure that the section in the new language is pronounced correctly.
How the Lighthouse invalid
lang attribute audit fails #
Lighthouse flags elements that have a
lang attribute with an invalid value:
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 invalid
lang attribute values #
Use only valid BCP 47 language codes in all
lang attribute values.