Discoverability · 30 points
Language attribute
One check, stated three ways: what we measure, what would make it wrong, and how to confirm it yourself.
What this measures
The lang attribute on the <html> element, and whether it is non-empty. Nothing else about language is inferred — no hreflang, no content translation.
Where this check can be wrong
Missing lang costs almost nothing in practice on an English-only site; we count it because screen readers and translation tooling use it, not because Google does.
Verify it without taking our word for it
curl -s https://your.site | head -2 — the first tag should read <html lang="en">.