Language of Parts
The human language of each passage or phrase that differs from the page's default language must be programmatically determinable through a `lang` attribute on the containing element.
What it requires
WCAG 2.0 SC 3.1.2 extends 3.1.1 to mid-page language switches. A page set to `<html lang="en">` that contains a French quote needs `<span lang="fr">…</span>` around the quote so screen readers switch pronunciation rules. Same for product names that use non-English characters with specific phonetic rules.
For multilingual ecommerce with Shopify Markets, this matters when a single page renders content in mixed languages — usually marketing copy + a brand name in another language.
Common Shopify failure
Storefront with multilingual product descriptions where French-language phrases inside English-language paragraphs lack `lang="fr"` markup. Screen readers pronounce the French as if it were English, garbling the words.
How to fix it
Auto-fix detects high-confidence non-default-language passages and wraps them in `<span lang="…">`. Lower-confidence cases are flagged for merchant review.
Primary source: W3C — WCAG 2.0 Understanding 3.1.2