Index: app/controllers/application.rb
===================================================================
--- app/controllers/application.rb	(revision 2383)
+++ app/controllers/application.rb	(working copy)
@@ -65,19 +65,23 @@
   
   def set_localization
     User.current.language = nil unless User.current.logged?
-    lang = begin
-      if !User.current.language.blank? && GLoc.valid_language?(User.current.language)
-        User.current.language
-      elsif request.env['HTTP_ACCEPT_LANGUAGE']
-        accept_lang = parse_qvalues(request.env['HTTP_ACCEPT_LANGUAGE']).first.downcase
-        if !accept_lang.blank? && (GLoc.valid_language?(accept_lang) || GLoc.valid_language?(accept_lang = accept_lang.split('-').first))
-          User.current.language = accept_lang
-        end
-      end
-    rescue
-      nil
-    end || Setting.default_language
-    set_language_if_valid(lang)    
+    if !Setting.static_language?
+        lang = begin
+          if !User.current.language.blank? && GLoc.valid_language?(User.current.language)
+            User.current.language
+          elsif request.env['HTTP_ACCEPT_LANGUAGE']
+            accept_lang = parse_qvalues(request.env['HTTP_ACCEPT_LANGUAGE']).first.downcase
+            if !accept_lang.blank? && (GLoc.valid_language?(accept_lang) || GLoc.valid_language?(accept_lang = accept_lang.split('-').first))
+              User.current.language = accept_lang
+            end
+          end
+        rescue
+          nil
+        end || Setting.default_language
+        set_language_if_valid(lang)
+    else
+        lang = Setting.default_language
+    end
   end
   
   def require_login
Index: app/views/settings/_display.rhtml
===================================================================
--- app/views/settings/_display.rhtml	(revision 2383)
+++ app/views/settings/_display.rhtml	(working copy)
@@ -7,6 +7,9 @@
 <p><label><%= l(:setting_default_language) %></label>
 <%= select_tag 'settings[default_language]', options_for_select( lang_options_for_select(false), Setting.default_language) %></p>
 
+<p><label><%= l(:setting_static_language) %></label>
+<%= check_box_tag 'settings[static_language]', 1, Setting.static_language? %><%= hidden_field_tag 'settings[static_language]', 0 %></p>
+
 <p><label><%= l(:setting_date_format) %></label>
 <%= select_tag 'settings[date_format]', options_for_select( [[l(:label_language_based), '']] + Setting::DATE_FORMATS.collect {|f| [Date.today.strftime(f), f]}, Setting.date_format) %></p>
 
Index: config/settings.yml
===================================================================
--- config/settings.yml	(revision 2383)
+++ config/settings.yml	(working copy)
@@ -143,3 +143,5 @@
     To change your notification preferences, please click here: http://hostname/my/account
 gravatar_enabled:  
   default: 0
+static_language:
+  default: 0
Index: lang/en.yml
===================================================================
--- lang/en.yml	(revision 2383)
+++ lang/en.yml	(working copy)
@@ -228,6 +228,7 @@
 setting_gravatar_enabled: Use Gravatar user icons
 setting_diff_max_lines_displayed: Max number of diff lines displayed
 setting_repository_log_display_limit: Maximum number of revisions displayed on file log
+setting_static_language: Disable automated language-guessing based on HTTP_ACCEPT_LANGUAGE HTTP-header
 
 permission_edit_project: Edit project
 permission_select_project_modules: Select project modules