Success Criterion 3.1.1
Conformance level A

3.1.1 · Language of Page

Lesson overview · Language of Page

In plain language

The page's language must be declared in code (lang attribute) and be correct.

Who it affects

Screen-reader users who need correct pronunciation, and tools that depend on language metadata.

How to check

View source: <html lang='..'> must exist and match the page language — including after switching site language.

Common misconception

Setting lang="en" once in the template feels like a one-time task. It breaks the moment a site adds a language switcher and forgets to update the attribute when the user changes languages.

Learn more

Understanding Understanding this success criterion (opens in a new tab)

Scenarios in this lesson

Page Published With No Language Declared in the Code
HTML Element Missing Its Language Attribute Entirely
Page’s Declared Language Not Matching Its Actual Content
Language Attribute Set to an Invalid or Malformed Value
Language Switcher That Doesn’t Update the Page’s Lang Attribute
Language Attribute Set on the Body Instead of the HTML Root
Multilingual Site Serving Every Locale With the Same Lang Value
PDF Document Published With No Language Metadata Set