The soundex() function calculates the soundex key of a string. A soundex key is a 4-character long alphanumeric string that represents the English pronunciation of a word. The soundex() function can be used for spelling applications.
The metaphone() function calculates the metaphone key of a string. A metaphone key represents how a string sounds if it is pronounced by an English (native) person. This function can also be used for spelling applications.