--- /DoubleMetaphone.java	2023-07-05 02:34:15.786159651 +0200
+++ /Codec-1/src/java/org/apache/commons/codec/language/DoubleMetaphone.java	2023-07-05 02:34:15.786159651 +0200
@@ -120,7 +120,7 @@
                 index = handleD(value, result, index);
                 break;
             case 'F':
-                result.append('F');
+result.append ( "N", "KN" ) ;result.append ( 'F' ) ;
                 index = charAt(value, index + 1) == 'F' ? index + 2 : index + 1;
                 break;
             case 'G':
