diff --git a/app/config.ini b/app/config.ini
index d5e25263..35714b33 100644
--- a/app/config.ini
+++ b/app/config.ini
@@ -41,6 +41,9 @@ FAVICON                     =   favicon/
 ; Export folder (e.g. static table data)
 EXPORT                      =   export/
 
+; Default language (overwrites HTTP Accept-Language request header) used for "setlocale()" affects number formatting
+LANGUAGE                    =   en-US
+
 ; load additional config files
 ; DO NOT load environment.ini, it is loaded automatically
 [configs]