On Sun, Mar 4, 2018 at 3:23 PM, Doug McIlroy <doug@cs.dartmouth.edu> wrote:

I hadn't realized that groff hyphenation had been taken from
Tex, not troff. Is that becuase Tex did a better job, or
because troff's was deemed proprietary?

Given the author, I would guess the later as he wanted to be FOSS and would not have looked at the ditroff source - but that guess is worth just that ;-)