Dear Jon,

I'm probably not the right person to answer your questions but will
try the best I can.

> Jim or Mahinda,
>
> 1. Do most commentaries remain untranslated into English?

Yes. I don't know of any complete English translation of the
commentaries (a.t.thakathaa-s) for the Vinayapi.taka and the first
four nikaayas of the Suttantapi.taka but portions have been
translated. Most of the available translations are for works found in
the Khuddakanikaaya and the Abhidhammapi.taka.

> 2. Are there many commentaries (atha-katha) and sub-commentaries
> (tika?) that use stories like the Dhammapada Commentary?

I think you will probably find stories here and there throughout most
of the commentaries. The English translation (by Burlingame) of the
Dhammapada commentary leaves out the word-by-word commentary on the
verses as is also the case with Cowell's Jaataka translation except
for the occasional footnote. I'm not sure of the situation with the
subcommentaries.

> 3. Do you know a good description and explanation of Athakathas and
> Tikas?

No, not off-hand nor do I know of any work to point you to that can
provide a good description and explanation in English. You might try
the English introductions to the commentaries published by PTS like
the one for the Diighanikaayat.t.hakathaa-pura.na.tiikaa for a
general introduction to .tiikaa-s. The Visuddhimagga is a commentary
and ~Naa.namoli's translation will give you some idea of what a
commentary does.

> They seem to maybe play a linguistic role too by clearing up any
> ambiguity in the meaning of the text.

Yes, I agree and they do play a very important linguistic role in
explaining the meaning of words and phrases in the Tipi.taka. And
the .tiikaa-s explain the a.t.thakathaa-s. Instead of two layers of
commentaries, there can also be three layers as with the
Abhidhammapi.taka: a.t.thakathaa, muula.tiikaa, and anu.tiikaa. The
amount of material available in Pali is enormous but most of it
remain untranslated into English.

Best wishes,
Jim