Multilingual SEO architecture for expert-led companies.

The three layers

Multilingual SEO has three layers: URL design, content modelling, and entity signalling. They interact.

URL design is where the structure starts. The two patterns that work for expert-led companies are subdirectory localisation (/de/, /es/) and subdomain localisation. Subdirectory localisation keeps the entity graph unified.

Content modelling is the second layer. A page in three languages is not three pages; it is one page with three locales.

hreflang and the redirect problem

hreflang is a signal, not a redirect. It tells search engines which page is the canonical version for which language and market. It does not replace redirects.

The most common mistake we see is hreflang without redirects. A German user reaches the French homepage, sees a German hreflang, and never gets to the German homepage.

The right pattern is: redirect on locale, hreflang on every page pointing at every other locale, and a canonical URL that does not change with locale.

Entity signals

The third layer is entity signalling. Generative systems and knowledge graphs treat a business's pages in different languages as the same entity unless told otherwise.

For a unified entity, every page across every locale uses the same Organization @id. The schema block declares knowsLanguage and areaServed. Pages that target a specific locale add inLanguage.

What to do when a redesign happens

Redesigns break multilingual architecture more often than they fix it. URL changes, redirects, and content model rewrites each carry risk.

Before any redesign, document the current multilingual architecture: every URL by locale, every hreflang pair, every schema block, every redirect.

Operational notes

Editorial workflow is where multilingual architecture lives or dies. If the editorial system forces editors to copy-paste between language versions, drift is inevitable.

Translation is not localisation. Localisation is a commercial and editorial discipline. Treating localisation as a translation step is the single most common structural mistake.