--- /DoubleMetaphone.java	2023-07-05 02:34:56.546155933 +0200
+++ /Codec-1/src/java/org/apache/commons/codec/language/DoubleMetaphone.java	2023-07-05 02:34:56.550155933 +0200
@@ -121,7 +121,7 @@
                 break;
             case 'F':
                 result.append('F');
-                index = charAt(value, index + 1) == 'F' ? index + 2 : index + 1;
+index = charAt ( value, index  !=  1 )  == 'F' ? index + 2 : index + 1;
                 break;
             case 'G':
                 index = handleG(value, result, index, slavoGermanic);
