Multilingual SEO: Best Practices for Multilingual Websites

Why multilingual SEO matters for DACH companies

If you run a B2B company in Austria and want to grow beyond Austria's borders, there is no way around multilingual SEO. Language on the web is heavily skewed: English is the content language of 49.3% of the top 10 million websites, German of only 5.9% (W3Techs, as of December 2025). On a global scale, German-language content is therefore a niche. That makes German-speaking markets attractive for specialized providers, but also linguistically demanding.

Language drives buying behavior. According to an international study by CSA Research, 76% of online shoppers prefer products with information in their native language, and 40% never buy from websites in other languages (8,709 consumers in 29 countries, 2020). A well-localized language version is therefore a prerequisite for conversion, not a convenience feature.

The home market itself is close to digital saturation: at the start of 2025, Austria had 8.69 million internet users at 95.3% online penetration. Growth here comes less from more users than from better visibility in the right language variants, meaning de-AT, de-DE, de-CH, and then further languages.

Domain strategy: ccTLD, subfolder, or subdomain

The fundamental decision in internationalization concerns the URL structure. There are three models:

ccTLD (country code top-level domain): Separate domains for each country, such as example.at, example.de, example.ch. The advantage is a strong geographic signal and high user trust in the respective country. The drawbacks are high maintenance effort and the fact that each domain has to build its domain authority separately.

Subfolder (subdirectory): One domain with language paths, such as example.com/at/ and example.com/de/. The advantage is consolidated domain authority, since all content shares ranking signals. This is usually the most pragmatic choice for mid-sized DACH companies.

Subdomain: Languages on their own subdomains, such as at.example.com. Technically flexible, but Google tends to treat subdomains as separate websites, so authority carries over less well.

In many cases, the data favors the subfolder strategy. A case study by Searchviu documents how the provider NFON migrated from several ccTLDs to a unified gTLD directory structure: in Austria, organic traffic grew by 90% and organic leads by 100% in the first five months, and in Germany stable growth emerged for the first time in three years. The study's core finding: pages on the same domain share ranking signals with each other more easily. For most Austrian companies without large international teams, the subfolder option is therefore the lowest-risk choice.

Implementing hreflang correctly

hreflang is the central technical signal that tells Google which language and regional version of a page is intended for which users. Google offers three implementation methods: in the HTML head, in the HTTP header, and in the XML sitemap. For each project, pick one method and apply it consistently.

The structure of an hreflang value follows a fixed pattern: a language code in ISO 639-1 format, optionally followed by a region code in ISO 3166-1 Alpha 2 format. Correct values are therefore de, de-AT, de-DE, or de-CH. Made-up combinations or putting the country first would be wrong.

Three rules are mandatory:

Self-reference: Every page must also list itself in its hreflang list. If the self-reference tag is missing, Google often ignores the set.

Reciprocity (return links): If page A points to page B, page B must also point to A. hreflang only works bidirectionally.

x-default: The reserved value x-default defines the fallback page when no language or regional version matches the user's browser setting. This is often a language selection page or the main international version.

Example of a complete head block for an Austrian page:

```html
<link rel="alternate" hreflang="de-AT" href="https://example.com/at/" />
<link rel="alternate" hreflang="de-DE" href="https://example.com/de/" />
<link rel="alternate" hreflang="en" href="https://example.com/en/" />
<link rel="alternate" hreflang="x-default" href="https://example.com/" />
```

Overall, hreflang adoption is moderate: according to the Web Almanac, in 2022, 9.6% of sites used hreflang on desktop and 8.9% on mobile, a slight increase over 2021. With de at 2.2%, German is one of the most common hreflang languages, tied with French.

Common hreflang errors and debugging

hreflang is error-prone. An Ahrefs study of 374,756 domains found that 67% of domains with hreflang have at least one error. The most common problems are documented: 56.3% are missing x-default, 18% are missing the self-reference tag, and 15.3% are missing reciprocal return links.

The typical sources of error in detail:

Conflict with canonical tags: If a page points to another language version via its canonical tag, that cancels out the hreflang logic. Every language version should canonicalize to itself.

Missing return links: The most common structural error. A single missing link breaks the entire chain.

Invalid language codes: Typos such as at instead of de-AT or outdated codes are ignored. Only ISO 639-1 and ISO 3166-1 Alpha 2 codes are valid.

References to redirected or broken URLs: hreflang must point to the final 200 URL, not to a redirect chain.

Google Search Console has not shown hreflang errors since Google discontinued the International Targeting report. For validation, you can use Merkle's hreflang Tags Testing Tool and crawlers such as Screaming Frog or Sitebulb, which list missing return links automatically.

DACH specifics: de-AT, de-DE, and de-CH

Not all German is the same. For DACH markets, a generic de is rarely enough if you serve several German-speaking countries. The differences are real and relevant to SEO:

Vocabulary: In Austria, people say Jänner instead of Januar (January), Sackerl instead of Tüte (bag), Erdäpfel instead of Kartoffeln (potatoes). In Switzerland, ß is dropped entirely in favor of ss. Terms like these are often direct search queries.

Regional search intent: Users search with local terms and expect local providers. A user in Austria searches for "Firmenbuch," a user in Germany for "Handelsregister," although both mean the same type of register (the commercial register).

Cultural tone: Form of address, level of formality, and examples should fit the market. A 1:1 copy of the page for Germany with only the Impressum (legal notice) swapped often feels foreign to Austrian users.

If you seriously serve all three markets, work with de-AT, de-DE, and de-CH and differentiate the content linguistically instead of just duplicating it.

International keyword research and content localization

The most common strategic mistake is translating keywords 1:1. Search terms emerge from a market's language and search intent, not from a literal translation.

Keyword research per market: Research search volumes and terms directly in the target language instead of translating German keywords. Your tools should be set to the respective country.

Check search intent: The same term can carry different intents in different markets. Check the SERPs in the target country.

Content localization goes far beyond the text:

Currency and units of measurement: Euro for AT/DE, Swiss francs for CH, and keep metric units consistent.

Legal notices: Austria imposes specific Impressum and disclosure requirements under the ECG (E-Commerce Act) and the Mediengesetz (Media Act) and also requires the VAT ID (UID number). These rules differ from those in Germany.

Tone and examples: References, case studies, and form of address should be rooted in the local market.

Real localization meets the expectations of the 76% of users who want to buy in their native language, instead of just providing formally translated pages.

Technical infrastructure: CDN, server location, and geo-targeting

Load time is a ranking factor and a particular challenge in international setups, because users are geographically distributed.

Use a CDN: A content delivery network with edge locations in Europe delivers content closer to the user and shortens load time evenly across all DACH markets.

Server location: For ccTLDs, the location is a weak additional geographic signal. For generic domains, it plays hardly any role in ranking, but it does matter for performance.

Geo-targeting in Search Console: With subfolder or subdomain structures, you used to be able to set a target country per directory. With ccTLDs, targeting is fixed by the domain extension and cannot be changed.

International link building strategies

Backlinks are market-specific. A backlink from a German site helps the Austrian language version only to a limited extent.

Local backlinks per market: Build links from domains in each target country, such as .at domains for the Austrian market. Local directories, industry media, and partnerships are relevant.

Factor domain authority into the structure: This is where the strategic advantage of the subfolder option shows. All backlinks strengthen one shared domain instead of being spread across several ccTLDs that each start from zero, as the NFON case study illustrates.

Migration and internationalization without losing visibility

Changing a domain or language structure is the biggest risk in international SEO. Mistakes directly cost rankings and traffic.

Complete redirect mapping: Every old URL needs a 301 redirect to the correct new counterpart in the right language. Avoid redirect chains.

Test hreflang before go-live: The new structure must be correctly linked before it goes live.

Close monitoring: Watch rankings, indexing, and traffic per market daily during the first weeks. The NFON study shows that temporary setbacks happen, but a consistently executed strategy leads to sustainable growth.

Programmatic SEO for scalable multilingual content

If you need to create many pages in several languages, such as location or product pages, programmatic SEO helps. Templates are filled from structured data sources to generate content at scale.

Clean data sources: The quality of the generated pages depends directly on the underlying data. Maintain structured, verified datasets.

Avoid thin content: Every generated page needs its own useful content. Google devalues mere placeholder variations without substance as thin content.

Quality assurance per language: Automated content must be spot-checked editorially in each language, especially for the subtle differences between de-AT, de-DE, and de-CH.

Metrics and measurement

In multilingual SEO, you measure success separately for each market and language version, never in aggregate:

Organic traffic per country/language: Segment by country in Search Console and by language in Analytics.

Rankings per target market: Track positions in localized SERPs with the correct location setting.

hreflang errors: Check your hreflang markup regularly with a crawler, since according to Ahrefs, 67% of domains with hreflang have at least one error.

Conversion per market: In the end, what counts is whether localized content leads to local conversions.

Bottom line

Multilingual SEO is an interplay of strategy, technology, and language. If you first choose a domain strategy that fits the size of your organization, then implement hreflang cleanly, and finally deliver real localization instead of translation, you build sustainable international visibility. For Austrian companies, differentiating between de-AT, de-DE, and de-CH is especially worthwhile. In practice it is often neglected, which is exactly why it gives you room to stand out.