How to fix valid lang on BigCommerce
Add a valid BCP 47 language code to every `lang` attribute on your pages so assistive technologies can read content in the correct language.
Steps for BigCommerce
- Go to BigCommerce admin → Storefront → My Themes → click 'Advanced' → 'Edit Theme Files' on your active theme.
- Open `templates/layout/base.html` (Cornerstone theme) and find the `<html` tag.
- BigCommerce injects `lang="{{locale_code}}"` automatically via Handlebars. Check that your store's locale is set correctly: Settings → Store Profile → Default Language.
- If a `lang` attribute is hard-coded to an invalid value in the template, replace it with `{{locale_code}}` to use the dynamic value.
- For any custom HTML widgets containing a `lang` attribute (added via Page Builder), edit the widget in Storefront → Page Builder, open the HTML block, and correct the value.
- Save and preview, then validate with the axe extension.
<html lang="en">
<!-- For a page in US English -->
<html lang="fr">
<!-- For a page primarily in French -->
<!-- Inline language switch for a passage in Spanish on an English page -->
<p lang="es">Bienvenido a nuestra tienda.</p>
<!-- Region-specific variant -->
<html lang="pt-BR">
<!-- Brazilian Portuguese -->What is valid lang?
Every HTML page has a `lang` attribute on the `<html>` tag (e.g. `<html lang="en">`) that tells browsers and assistive technologies what language the page is written in. When a page contains a passage in a *different* language, that section should also carry its own `lang` attribute (e.g. `<p lang="fr">`). The value must be a valid BCP 47 language tag — a standardised code like `en`, `en-US`, `fr`, `de`, or `zh-Hans`. An empty, misspelled, or made-up value (such as `lang=""` or `lang="english"`) fails WCAG Success Criterion 3.1.2 (Language of Parts).
Screen readers like JAWS, NVDA, and VoiceOver automatically switch their text-to-speech voice and pronunciation rules based on the `lang` attribute. If the value is missing or invalid, the reader mispronounces words — sometimes so badly that the content becomes completely unintelligible to blind or low-vision shoppers. Beyond accessibility, WCAG 3.1.2 is a Level AA requirement, meaning failing it exposes your store to legal risk under laws such as the ADA in the US, the European Accessibility Act, and equivalent legislation elsewhere. Google also uses language signals to serve your pages to the right audiences, so correct `lang` values support your international SEO.
See the complete Valid lang guide for every platform and the full background.
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