Multilingual SEO with Hreflang

What is hreflang?

Hreflang is a signal that tells search engines which language and/or regional version of the same content should be displayed to which user on a multilingual or multi-regional site. It is typically added to the <head> section of the page <link rel="alternate" hreflang="..."> ; alternatively, it can be defined via an HTTP header or a sitemap, but only one of these three methods should be used.

Hreflang does not indicate that a page is a “translation”; rather, it specifies that different language/region versions serving the same purpose are related to one another. For example, on an e-commerce site, prices in English may be displayed in USD, while prices in Turkish may be displayed in TL; hreflang links these two versions together to ensure the right user sees the correct version.

Hreflang is not a redirect mechanism; it does not automatically redirect the user to another language, but simply informs Google that “alternative versions of this page exist in these languages.” Google’s own geographic and language predictions largely determine which version the user will see.

Why is this important?

Without hreflang, Google might accidentally show a user the Turkish version of a site when they’re searching in English—or vice versa—which can cause the user to leave the page immediately (bounce). Proper use of hreflang ensures that every user sees the page that matches their language and region preferences, thereby improving the user experience and, indirectly, the conversion rate.

It also prevents confusion caused by duplicate content across different language versions of the same content: Google recognizes pages within the same hreflang group as alternatives to one another, rather than as competing pages that “steal” traffic from each other. This becomes even more critical in different regional variations of the same language (e.g., tr-TR and tr-CY).

When multiple equivalent SEO signals (such as canonical URLs, robots meta tags in robots.txt, and hreflang locations) serve the same purpose, it is better to choose a single source of truth: Repeating these signals in multiple formats does not improve SEO; it only adds the risk of inconsistency.

How to fix it?

Each language version must reference all other versions within the same group using hreflang (reciprocal—return—links are required); one-way links are ignored by Google.
For the default version that doesn’t correspond to any specific language, use the x-default value.
Write ISO language codes correctly; for example, for Turkish tr, for English en; combine with the region code if necessary (e.g., en-US).
Choose a single method: implement hreflang using either the HTML <link> tag or via the sitemap; do not use both at the same time—this creates a redundant, unnecessary signal and carries the risk of synchronization errors.
Remember that each page must also reference itself with hreflang (self-reference); the group must be complete.
As the site grows, manage hreflang maintenance not manually but through a mechanism automatically generated at the template/CMS level; manually added hreflang groups tend to fall out of sync over time.
When adding a new language version, update the reference list for all other versions until the page for that language is included in the existing hreflang group; omitting a version compromises the group’s consistency.
When performing automatic redirection based on the user’s browser language (e.g., JavaScript-based), ensure that bots are not subject to the same redirection; all language versions must remain crawlable for bots.

Example

<link rel="alternate" hreflang="tr" href="https://example.com/tr/page" />
<link rel="alternate" hreflang="en" href="https://example.com/en/page" />
<link rel="alternate" hreflang="x-default" href="https://example.com/en/page" />

Bad example: Referencing the English version with an hreflang on the Turkish page, but failing to add a backlink to the Turkish version on the English page—this one-way link is considered invalid by Google, and the group will not be recognized at all.

Common Mistakes

Implementing one-way hreflang (Page A references Page B, but Page B does not reference Page A).
Using incorrect or invalid language/region codes.
Creating confusion by repeating the same hreflang signal in both the HTML tag and the sitemap.
Failing to define the "x-default" version.
In the Seoraporu.co report, non-reciprocal hreflang links are listed as a separate warning; this is generally the most common hreflang error found on multilingual sites.