Add support for a language param

config/site_settings.yml

@@ -155,6 +155,11 @@ basic:
     hidden: true
     client: true
     validator: "AllowUserLocaleEnabledValidator"
+  set_locale_from_param:
+    default: false
+    hidden: true
+    client: true
+    validator: "AllowUserLocaleEnabledValidator"
   support_mixed_text_direction:
     client: true
     default: false

lib/discourse.rb

@@ -1215,7 +1215,8 @@ module Discourse
   end
 
   def self.anonymous_locale(request)
-    locale =
+    locale = request.params["lang"] if SiteSetting.set_locale_from_param
+    locale ||=
       HttpLanguageParser.parse(request.cookies["locale"]) if SiteSetting.set_locale_from_cookie
     locale ||=
       HttpLanguageParser.parse(