Patgen takes a list of hyphenated words and generates a set of
patterns that can be used by the \TeX 82 hyphenation algorithm.
The program is released to the public domain (as is this README file).

Patgen was originally written by Frank M. Liang as part of his
Stanford Ph.D. work, and has always been distributed alongside the
other programs coming from the Stanford TeX project. It was updated in
1991 by Peter Breitenlohner for the new 8-bit features of TeX version 3.
(These updates related to input/output and programming overhead; the
actual pattern generation algorithms were not changed.)

Patgen is currently maintained as part of TeX Live (https://tug.org/texlive).
Home page: https://ctan.org/pkg/patgen