[tex-hyphen] ruhyphen and ot2

[Per Starback]

Hi! I have set up for hyphenation of OT2 coded Russian,
with

	\def\Encoding{ot2}

in ruhyphen.tex. (I haven't changed anything else. I still use the
standard Pattern{al} for example.) When I use the following test
document I am surprised:

  \documentclass{article}
  \usepackage[OT2]{fontenc}
  \usepackage[russian]{babel}
  \begin{document}
  \showhyphens{perevodyat}
  \end{document}

I get

  Underfull \hbox (badness 10000) in paragraph at lines 5--5
  [] \OT2/cmr/m/n/10 pe-re-vo-dy-at
                                ^
Note hyphenation in letter ya --/

So I guess it is necessary to add patterns like y8a when using OT2?