Caverphone

The rules of the algorithm are applied consecutively to any particular name, as a series of replacements.

The algorithm is as follows:

1. Convert to lowercase
2. Remove anything not A-Z
3. If the name starts with...
   1. cough, replace it by cou2f
   2. rough, replace it by rou2f
   3. tough, replace it by tou2f
   4. enough, replace it by enou2f
   5. gn, replace it by 2n
4. If the name ends with
   1. mb, replace it by m2
5. Replace
   1. cq with 2q
   2. ci with si
   3. ce with se
   4. cy with sy
   5. tch with 2ch
   6. c with k
   7. q with k
   8. x with k
   9. v with f
   10. dg with 2g
   11. tio with sio
   12. tia with sia
   13. d with t
   14. ph with fh
   15. b with p
   16. sh with s2
   17. z with s
   18. any initial vowel with an A
   19. all other vowels with a 3
   20. 3gh3 with 3kh3
   21. gh with 22
   22. g with k
   23. groups of the letter s with a S
   24. groups of the letter t with a T
   25. groups of the letter p with a P
   26. groups of the letter k with a K
   27. groups of the letter f with a F
   28. groups of the letter m with a M
   29. groups of the letter n with a N
   30. w3 with W3
   31. wy with Wy
   32. wh3 with Wh3
   33. why with Why
   34. w with 2
   35. any initial h with an A
   36. all other occurrences of h with a 2
   37. r3 with R3
   38. ry with Ry
   39. r with 2
   40. l3 with L3
   41. ly with Ly
   42. l with 2
   43. j with y
   44. y3 with Y3
   45. y with 2
6. remove all
   1. 2
   2. 3
7. put six 1 on the end
8. take the first six characters as the code

1. Start with a word
2. Convert to lowercase
3. Remove anything not in the standard alphabet (typically a-z)^{[note 1]}
4. Remove final e
5. If the name starts with
   1. cough make it cou2f
   2. rough make it rou2f
   3. tough make it tou2f
   4. enough make it enou2f
   5. trough make it trou2f
   6. gn make it 2n
6. If the name ends with
   1. mb make it m2
7. Replace
   1. cq with 2q
   2. ci with si
   3. ce with se
   4. cy with sy
   5. tch with 2ch
   6. c with k
   7. q with k
   8. x with k
   9. v with f
   10. dg with 2g
   11. tio with sio
   12. tia with sia
   13. d with t
   14. ph with fh
   15. b with p
   16. sh with s2
   17. z with s
   18. an initial vowel^{[note 2]} with an A
   19. all other vowels with a 3
   20. j with y
   21. an initial y3 with Y3
   22. an initial y with A
   23. y with 3
   24. 3gh3 with 3kh3
   25. gh with 22
   26. g with k
   27. groups of the letter s with a S
   28. groups of the letter t with a T
   29. groups of the letter p with a P
   30. groups of the letter k with a K
   31. groups of the letter f with a F
   32. groups of the letter m with a M
   33. groups of the letter n with a N
   34. w3 with W3
   35. wh3 with Wh3
   36. if the name ends in w replace the final w with 3
   37. w with 2
   38. an initial h with an A
   39. all other occurrences of h with a 2
   40. r3 with R3
   41. if the name ends in r replace the final r with 3
   42. r with 2
   43. l3 with L3
   44. if the name ends in l replace the final l with 3
   45. l with 2
8. remove all 2s
9. if the name end in 3, replace the final 3 with A
10. remove all 3s
11. put ten 1s on the end
12. take the first ten characters as the code

• Soundex
• New York State Identification and Intelligence System
• Match rating approach
• Metaphone
• Cologne phonetics

• Caversham Project - Caversham data set of names and accents in the southern part of Dunedin, New Zealand in 1893-1938.
• Original (2002) Caverphone algorithm
• Revised (2004) Caverphone algorithm
• Implementations:
  • C# Revised Implementation
  • Java implementation in the Apache Commons Codec project
  • PHP implementation
  • Python Implementation caverphone algorithm (version 2.0) - AdvaS Advanced Search project