The Metaphone algorithm was Created by Lawrence Philips. The Metaphone algorithm was first introduced in an article published in "Computer Language" December 1990 issue. Since its inception the algorithm has been updated by the original author, Lawrence Phillips, twice. The second iteration, released in 2000 was the Double Metaphone and the most recent update is the Metaphone 3, realease in 2009 under a proprietary license and as such is unavailable without a purchased license.
There are 16 distinct "consonant sounds" in the metaphone algorithm. B
, F
, H
, J
, K
, L
, M
, N
, O
, P
, R
, S
, T
, W
, X
, Y
and 0
(zero) where 0
represents the th
sound.