--- a/src/testdir/test63.in
+++ b/src/testdir/test63.in
@@ -60,7 +60,7 @@ STARTTEST
 :else
 :  let @r .= "FAILED\n"
 :endif
-:" --- Check that "matchdelete()" returns 0 if succesfull and otherwise -1.
+:" --- Check that "matchdelete()" returns 0 if successful and otherwise -1.
 :let @r .= "*** Test 6: "
 :let m = matchadd("MyGroup1", "TODO")
 :let r1 = matchdelete(m)
@@ -117,7 +117,7 @@ STARTTEST
 :" --- Check that "setmatches()" will not add two matches with the same ID. The
 :" --- expected behaviour (for now) is to add the first match but not the
 :" --- second and to return 0 (even though it is a matter of debate whether
-:" --- this can be considered succesfull behaviour).
+:" --- this can be considered successful behaviour).
 :let @r .= "*** Test 9: "
 :let r1 = setmatches([{'group': 'MyGroup1', 'pattern': 'TODO', 'priority': 10, 'id': 1}, {'group': 'MyGroup2', 'pattern': 'FIXME', 'priority': 10, 'id': 1}])
 :if getmatches() == [{'group': 'MyGroup1', 'pattern': 'TODO', 'priority': 10, 'id': 1}] && r1 == 0
@@ -127,7 +127,7 @@ STARTTEST
 :endif
 :call clearmatches()
 :unlet r1
-:" --- Check that "setmatches()" returns 0 if succesfull and otherwise -1.
+:" --- Check that "setmatches()" returns 0 if successful and otherwise -1.
 :" --- (A range of valid and invalid input values are tried out to generate the
 :" --- return values.)
 :let @r .= "*** Test 10: "