Unexpected language code

asa · May 9, 2026, 5:23am

I ran a Google Pagespeed test on my instance and received the following message:

I can’t explain what’s causing it. Is there an error in the translator?

Moin · May 9, 2026, 3:05pm

I think the invalid code comes from Discourse.

app/views/common/_hreflang_tags.html.erb

0ae63cf57


      
          <% if SiteSetting.content_localization_enabled && SiteSetting.content_localization_crawler_param %>
            <% locales = SiteSetting.content_localization_supported_locales&.split('|') || [] %>
            <% if locales.any? %>
              <% current_path = request.path %>
              <% canonical_url = "#{Discourse.base_url}#{current_path}" %>
              <link rel="alternate" href="<%= canonical_url %>" hreflang="x-default" />
              <% locales.each do |locale| %>
                <link rel="alternate" href="<%= canonical_url %>?<%= Discourse::LOCALE_PARAM %>=<%= locale %>" hreflang="<%= locale %>" />
              <% end %>
            <% end %>
          <% end %>

Maybe instead of hreflang="<%= locale %>" it should be hreflang="<%= locale.tr('_', '-') %>" to replace the underscore.

asa · May 11, 2026, 12:43pm

I have submitted a Pull Request to fix this in the Discourse repository:

github.com/discourse/discourse

FIX: Use hyphens instead of underscores for hreflang tags (#39884)

main ← asa0w0:main

opened 12:40PM - 11 May 26 UTC

asa0w0

+1 -1

## Problem The AI localization feature currently generates `hreflang` tags usin…g underscores (e.g., `pt_BR`). According to ISO 639-1 and SEO standards, search engines like Google expect hyphens (e.g., `pt-BR`). This causes validation errors in tools like PageSpeed Insights and Google Search Console ("Unexpected language code"). ## Solution This PR applies `.tr('_', '-')` to the `locale` string within the `hreflang` attribute. This ensures that: 1. The `href` URL remains functional (still using the internal underscore format for the parameter). 2. The `hreflang` metadata becomes SEO-compliant by using the hyphen format. ## Validation Confirmed that this change transforms codes like `pt_BR` into `pt-BR` in the rendered HTML header, resolving the "Unexpected language code" error.

This change ensures the hreflang attribute is SEO-compliant while keeping the internal locale parameters functional.

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Unexpected language code

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