https://github.com/Beep6581/RawTherapee/issues/6452

Index: rtgui/multilangmgr.cc
--- rtgui/multilangmgr.cc.orig
+++ rtgui/multilangmgr.cc
@@ -143,8 +143,8 @@ void setGtkLanguage(const Glib::ustring &language)
         lang = lang + ".UTF-8"; // According to Apple documentation, UTF-8 is a built-in encoding on all platforms on which macOS runs
 
         g_setenv("LANG", lang.c_str(), true);
-        setlocale(LC_ALL, lang.c_str());
-        setlocale (LC_NUMERIC, "C"); // Force decimal point to dot.
+        //setlocale(LC_ALL, lang.c_str());
+        //setlocale (LC_NUMERIC, "C"); // Force decimal point to dot.
 
 #else
 
@@ -395,9 +395,9 @@ Glib::ustring MultiLangMgr::getOSUserLanguage ()
 
     // Set locale environment data
     locale = locale + ".UTF-8"; // According to Apple documentation, UTF-8 is a built-in encoding on all platforms on which macOS runs
-    g_setenv("LANG", locale.c_str(), true);
-    setlocale(LC_ALL, locale.c_str());
-    setlocale (LC_NUMERIC, "C"); // Force decimal point to dot.
+    //g_setenv("LANG", locale.c_str(), true);
+    //setlocale(LC_ALL, locale.c_str());
+    //setlocale (LC_NUMERIC, "C"); // Force decimal point to dot.
 
     langName = localeToLang(locale);
     
