diff -urN Pale-Moon-27.4.0_Release/browser/app/profile/palemoon.js Pale-Moon-27.4.0_Release-patched/browser/app/profile/palemoon.js
--- Pale-Moon-27.4.0_Release/browser/app/profile/palemoon.js	2017-07-10 22:23:16.000000000 +1000
+++ Pale-Moon-27.4.0_Release-patched/browser/app/profile/palemoon.js	2017-07-13 00:11:50.435618980 +1000
@@ -467,6 +467,9 @@
 pref("general.warnOnAboutConfig",                 false);
 #endif
 
+// Use system environment variable to choose locale
+pref("intl.locale.matchOS", true);
+
 // This is the pref to control the location bar, change this to true to 
 // force this - this makes the origin of popup windows more obvious to avoid
 // spoofing. We would rather not do it by default because it affects UE for web