diff --git a/reactos/include/psdk/winnt.h b/reactos/include/psdk/winnt.h
index f1d2120d6a7..711dcc96642 100644
--- a/reactos/include/psdk/winnt.h
+++ b/reactos/include/psdk/winnt.h
@@ -1023,6 +1023,7 @@ typedef enum
 #define SUBLANG_SPANISH_GUATEMALA   0x04
 #define SUBLANG_SPANISH_HONDURAS   0x12
 #define SUBLANG_SPANISH_MEXICAN   0x02
+#define SUBLANG_SPANISH_MODERN   0x03
 #define SUBLANG_SPANISH_NICARAGUA   0x13
 #define SUBLANG_SPANISH_PANAMA   0x06
 #define SUBLANG_SPANISH_PARAGUAY   0x0f