Language Codes in SEO (hreflang) — Multilingual SEO Guide

Q: Language Codes in SEO (hreflang) — Multilingual SEO Guide

## hreflang and Language Codes for SEO The hreflang attribute tells search engines which language and regional version of a page to show to users in different locales. Getting the language codes right is critical for international SEO. ### hreflang Syntax html <link rel="

How to use hreflang tags with correct language codes for multilingual SEO, including implementation patterns and common pitfalls.

SEO

Detailed Explanation

hreflang and Language Codes for SEO

The hreflang attribute tells search engines which language and regional version of a page to show to users in different locales. Getting the language codes right is critical for international SEO.

hreflang Syntax

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

Rules for hreflang Values

Use ISO 639-1 two-letter language codes
Optionally add ISO 3166-1 alpha-2 country codes after a hyphen
Language code is required; region code is optional
x-default designates the fallback page for unmatched languages
Every page listed in hreflang must link back to all others (bidirectional)

Common Patterns

Language only (recommended when content is not region-specific):

<link rel="alternate" hreflang="en" href="/en/page" />
<link rel="alternate" hreflang="ja" href="/ja/page" />
<link rel="alternate" hreflang="de" href="/de/page" />

Language + region (when content varies by country):

<link rel="alternate" hreflang="en-US" href="/en-us/page" />
<link rel="alternate" hreflang="en-GB" href="/en-gb/page" />
<link rel="alternate" hreflang="pt-BR" href="/pt-br/page" />
<link rel="alternate" hreflang="pt-PT" href="/pt-pt/page" />

Implementation Methods

HTML <link> tags in <head> (most common)
HTTP headers (useful for PDFs and non-HTML resources)
XML sitemap (best for large sites with many language versions)

Sitemap Implementation

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

Common Mistakes

Using en-uk instead of en-GB (UK is not a valid ISO 3166-1 code for the country; GB is)
Missing the x-default tag
Non-reciprocal links (page A links to B, but B does not link back to A)
Using ISO 639-2 three-letter codes (hreflang requires two-letter ISO 639-1)
Pointing hreflang to non-canonical URLs

Use Case

Every multilingual website needs hreflang for proper international SEO. Without it, search engines may show the wrong language version to users, leading to high bounce rates and lost traffic. E-commerce sites, SaaS platforms, and media companies with international audiences rely on correct hreflang implementation.

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