diff --git a/src/spellsuggest.c b/src/spellsuggest.c
index 2951eea..a6dbc78 100644
--- a/src/spellsuggest.c
+++ b/src/spellsuggest.c
@@ -1178,6 +1178,11 @@
     p = su->su_badptr + su->su_badlen;
     (void)spell_casefold(curwin, p, (int)STRLEN(p), fword + n, MAXWLEN - n);
 
+    // Make sure the resulting text is not longer than the original text.
+    n = (int)STRLEN(su->su_badptr);
+    if (n < MAXWLEN)
+	fword[n] = NUL;
+
     for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi)
     {
 	lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);