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( Understandable / WCAG 3.1.1 )

HTML lang attribute is not a valid BCP 47 tag

This check maps to Language of Page. Use the guidance below to confirm the issue, understand who it affects and ship a fix.

Moderate Level A WCAG 3.1.1 — Language of Page

What’s wrong

The html lang attribute is present but uses an invalid language code.

Why it matters

Screen readers use lang to choose pronunciation and voice rules. Invalid codes can cause incorrect speech output for every page element.

How to fix it

Use semantic HTML and valid ARIA so assistive technology gets the same state and structure as sighted users. Keep labels and states explicit in markup.

Before
<html lang="english">
After
<html lang="en">

If this pattern is generated by a component, fix it once in the shared component so every instance inherits the accessible behavior.

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