What does the HTML lang check verify?
It checks that the page declares its primary language correctly. Specifically:
- Attribute present — the
<html>tag has alangattribute. - Valid value — it uses a valid language code (like
en,de, oren-GBfor region). - Matches content — the declared language matches the actual language of the page's content.
A valid lang attribute matching the content passes; a present but generic or imprecise declaration is a warning; a missing lang attribute is a fail.
How is it evaluated, and how is it scored?
GEObubbly checks the <html> tag for a valid lang attribute. It's a core, scored International SEO check that runs directly against the page's markup.
Why the lang attribute matters for SEO and GEO
The lang attribute on the <html> element declares the primary language of the page — for example <html lang="en"> or <html lang="en-GB"> for a regional variant. It's small but does real work. For accessibility, screen readers use it to choose the correct pronunciation and voice, so a French page declared as English would be read aloud with the wrong accent and rhythm — confusing or unusable for the listener. For browsers, it informs spell-checking and offers of translation. For engines, it's a clear signal of the page's language, which supports correct handling and helps your content be served to the right audience. It's also the foundation of international SEO: before hreflang can map language and region variants of a page, each page needs to declare its own language clearly. Getting it right is trivial — one attribute with a valid code that matches the content — yet it's commonly missing or left at a template default that doesn't match the actual language. For GEO, a correctly-declared language helps AI engines understand and correctly attribute your content by locale. It's the starting point of International SEO.