diff --git a/firmware/arabjoin.h b/firmware/arabjoin.h
index e69de29bb2..0085b31f4c 100644
--- a/firmware/arabjoin.h
+++ b/firmware/arabjoin.h
@@ -0,0 +1,10 @@
+typedef struct {
+    unsigned short isolated;
+    unsigned short final;
+    unsigned short medial;
+    unsigned short initial;
+} arab_t;
+
+extern const arab_t zwj; /* zero-width joiner */
+extern const arab_t lamaleph[]; /* lam-aleph ligatures */
+extern const arab_t jointable[]; /* lookup table for arabic joining */