Clipper had SOUNDEX function, which was used to search in flat-file databases for descriptive names. SEEK SOUNDEX("Smith") and SEEK SOUNDEX("Smythe") would return the same result. https://www.itlnet.net/programming/program/Reference/c53g01c...

But Harbour, an open-source implementation of Clipper superseded it with Metaphone - https://harbour.github.io/doc/hbnf.html#ft_metaph