⚠️ Issue: invalid locale (future detection)

Invalid Locale Test Page

This page has an invalid lang attribute in the HTML tag: lang="invalid-lang-code"

What's wrong?

HTML lang attribute uses non-standard language code
Should use ISO 639-1 language codes (en, fr, es, de, etc.)
Can include optional region code (en-US, en-GB, fr-CA, etc.)
Search engines and assistive technologies cannot identify page language
Screen readers may use wrong pronunciation

Expected Detection:

Check: locale (automatic, detection not yet implemented)

Status: Future Issue

Detection logic would need to:

Extract lang attribute from HTML tag
Validate against ISO 639-1 language code list
Optionally validate region codes (ISO 3166-1 alpha-2)
Flag pages with missing or invalid lang attribute

Common Invalid Examples:

lang="english" - Should be lang="en"
lang="eng" - Should be lang="en" (ISO 639-1, not 639-2)
lang="EN" - Should be lowercase: lang="en"
lang="en_US" - Should use hyphen: lang="en-US"
lang="us" - US is a country, not language. Use lang="en-US"

Valid Examples:

<html lang="en">           <!-- English -->
<html lang="en-US">        <!-- English (United States) -->
<html lang="en-GB">        <!-- English (United Kingdom) -->
<html lang="fr">           <!-- French -->
<html lang="fr-CA">        <!-- French (Canada) -->
<html lang="es">           <!-- Spanish -->
<html lang="es-MX">        <!-- Spanish (Mexico) -->
<html lang="de">           <!-- German -->
<html lang="ja">           <!-- Japanese -->
<html lang="zh-Hans">      <!-- Chinese (Simplified) -->
<html lang="zh-Hant">      <!-- Chinese (Traditional) -->

How to Fix:

In Next.js layout.tsx:

export default function RootLayout({ children }) {
  return (
    <html lang="en">  {/* Use valid ISO 639-1 code */}
      <body>{children}</body>
    </html>
  )
}

Why This Matters:

Helps search engines understand content language
Screen readers use correct pronunciation and voice
Browsers can offer translation accurately
Improves international SEO
Required for WCAG accessibility compliance