What's wrong
Values like `lang="english"` or malformed region codes cause speech synthesis software to fail.
Who it affects
Screen readers fall back to default speech synthesizers or report language parsing errors.
How to fix on Shopify
Always use Shopify's native `request.locale.iso_code` object rather than hardcoded language strings.
Code example
Problematic Code
LIQUID
<html lang="english">Recommended Accessible Code
LIQUID
<html lang="{{ request.locale.iso_code }}">How to check your fix
Validate the `lang` tag against the IANA language subtag registry (e.g. `en`, `en-US`, `fr`, `de`).