diff --git a/doc/misc/Makefile.in b/doc/misc/Makefile.in
index 290c88248fa..a0b871f91b7 100644
--- a/doc/misc/Makefile.in
+++ b/doc/misc/Makefile.in
@@ -66,6 +66,7 @@ MAKEINFO_OPTS = --force -I$(emacsdir)
 ifeq ($(DOCLANG),)
 DOCLANG:=default
 else ifeq ($(wildcard $(srcdir)/../translations/$(DOCLANG)/info_common.mk),)
+$(error No manual language $(DOCLANG) found)
 DOCLANG:=default
 endif