diff --git a/src/libespeak-ng/readclause.c b/src/libespeak-ng/readclause.c
index c660c89a..719ed91a 100644
--- a/src/libespeak-ng/readclause.c
+++ b/src/libespeak-ng/readclause.c
@@ -34,6 +34,7 @@
 #include <espeak-ng/espeak_ng.h>
 #include <espeak-ng/speak_lib.h>
 #include <espeak-ng/encoding.h>
+#include <ucd/ucd.h>
 
 #include "error.h"
 #include "speech.h"