diff --git a/rnotes/Makefile b/rnotes/Makefile
index a904bf9..10e5f5f 100644
--- a/rnotes/Makefile
+++ b/rnotes/Makefile
@@ -21,7 +21,7 @@
 #==============================================================================
 # Configuration
 #==============================================================================
-lang = en_US
+lang = en-US
 srcdir = SVG
 prefix = PNG
 datarootdir = $(prefix)/$(lang)