Editing Metaphone (section)

==Procedure==
Original Metaphone codes use the 16 [[consonant]] symbols 0BFHJKLMNPRSTWXY.<ref name="sound-ex">{{cite web|url=http://www.sound-ex.com/alternative_zu_soundex|title=Alternative to Soundex|website=www.sound-ex.com|access-date=16 May 2018 |archive-url=https://web.archive.org/web/20140306105535/http://www.sound-ex.com/alternative_zu_soundex |archive-date=6 March 2014 |url-status=usurped}}</ref> The '0' represents "[[Th (digraph)|th]]" (as an [[ASCII]] approximation of [[Theta|Θ]]), 'X' represents "[[Sh (digraph)|sh]]" or "[[Ch (digraph)|ch]]", and the others represent their usual English pronunciations.  The [[vowels]] AEIOU are also used, but only at the beginning of the code.<ref>{{cite web|url=http://www.morfoedro.it/doc.php?n=222&lang=en|title=Morfoedro - Technology|website=www.morfoedro.it|access-date=16 May 2018}}</ref> This table summarizes most of the rules in the original implementation:

# Drop duplicate adjacent letters, except for C.
# If the word begins with 'KN', 'GN', 'PN', 'AE', 'WR', drop the first letter.
# Drop 'B' if after 'M' at the end of the word.
# 'C' transforms to 'X' if followed by 'IA' or 'H' (unless in latter case, it is part of '-SCH-', in which case it transforms to 'K'). 'C' transforms to 'S' if followed by 'I', 'E', or 'Y'. Otherwise, 'C' transforms to 'K'.
# 'D' transforms to 'J' if followed by 'GE', 'GY', or 'GI'. Otherwise, 'D' transforms to 'T'.
# Drop 'G' if followed by 'H' and 'H' is not at the end or before a vowel. Drop 'G' if followed by 'N' or 'NED' and is at the end.
# 'G' transforms to 'J' if before 'I', 'E', or 'Y', and it is not in 'GG'. Otherwise, 'G' transforms to 'K'.
# Drop 'H' if after vowel and not before a vowel.
# 'CK' transforms to 'K'.
# 'PH' transforms to 'F'.
# 'Q' transforms to 'K'.
# 'S' transforms to 'X' if followed by 'H', 'IO', or 'IA'.
# 'T' transforms to 'X' if followed by 'IA' or 'IO'. 'TH' transforms to '0'. Drop 'T' if followed by 'CH'.
# 'V' transforms to 'F'.
# 'WH' transforms to 'W' if at the beginning. Drop 'W' if not followed by a vowel.
# 'X' transforms to 'S' if at the beginning. Otherwise, 'X' transforms to 'KS'.
# Drop 'Y' if not followed by a vowel.
# 'Z' transforms to 'S'.
# Drop all vowels unless it is the beginning.

This table does not constitute a complete description of the original Metaphone algorithm, and the algorithm cannot be coded correctly from it. Original Metaphone contained many errors and was superseded by Double Metaphone, and in turn Double Metaphone and original Metaphone were superseded by Metaphone 3, which corrects thousands of miscodings that will be produced by the first two versions.

To implement Metaphone without purchasing a (source code) copy of Metaphone 3, the reference implementation of Double Metaphone can be used.<ref>{{cite web |last=Philips |first=Lawrence |year=1999 |orig-date=1998 |url=http://aspell.net/metaphone/dmetaph.cpp |format=CPP |title=Double Metaphone |website=GNU Aspell |access-date=February 23, 2024}}</ref>  Alternatively, version 2.1.3 of Metaphone 3, an earlier 2009 version without a number of encoding corrections made in the current version, version 2.5.4, has been made available under the terms of the [[BSD License]] via the OpenRefine project.<ref>{{cite web | url=https://github.com/OpenRefine/OpenRefine/blob/master/main/src/com/google/refine/clustering/binning/Metaphone3.java | title=OpenRefine | website=[[GitHub]] | date=19 May 2022 }}</ref>