Nailing the SEO of a multilingual site (hreflang & co.)

A site in several languages multiplies your audience — as long as you avoid the technical pitfalls that can penalise you. Here's the method for clean multilingual SEO.

1. Choose the right URL structure

Three main options, each with its advantages:

For most projects, the subdirectory (/en/, /es/) is the best compromise. It's what we use, in fact.

2. Hreflang tags: the heart of the matter

The hreflang tells Google which version to show to which user. Without it, your versions compete with each other.

<link rel="alternate" hreflang="fr" href="https://site.com/" />
<link rel="alternate" hreflang="en" href="https://site.com/en/" />
<link rel="alternate" hreflang="es" href="https://site.com/es/" />
<link rel="alternate" hreflang="x-default" href="https://site.com/" />

Essential rules:

• Each page references itself and references its translations.
• The links must be reciprocal (A points to B and B to A).
• Add x-default for the default version.

3. Truly translate (not just the words)

Raw machine translation hurts both SEO and credibility. Best practices:

• Localise, don't just translate (currencies, examples, tone).
• Adapt the keywords: people don't search for the same thing in each language.
• Translate the tags too: title, description, alt attributes.

4. Avoid duplicate content

Two different languages are not duplicate content. However:

• Don't mix two languages on the same page.
• Avoid near-identical versions (e.g. fr-FR and fr-BE with no real difference) without regional hreflang.

5. Tutorial: a multilingual launch checklist

1. A chosen and consistent URL structure.
2. hreflang on all pages, reciprocal, with x-default.
3. A sitemap including all language versions.
4. Translated and optimised tags (title, description).
5. A clear, accessible language switcher.
6. Genuinely localised content, not machine-translated.

6. Measure by language

In your analytics tool and the Search Console, segment by language/country. You'll see which versions perform and where to invest.

Conclusion

A well-built multilingual site means flawless hreflang, clean URLs and genuinely localised content. Done right, it multiplies your reach. This site is multilingual FR/EN/ES following these principles — see our multilingual website offer or let's talk about yours.

FAQ

Is machine translation enough? For a draft, yes; for SEO and credibility, human proofreading is a must.

How many languages should you add? Only those where you have a real audience and the capacity to respond.