Re: Proposal: Ligatures w/ ZWJ in OpenType

From: Doug Ewell (
Date: Mon Jul 15 2002 - 11:58:06 EDT

Concerning the use of ZWJ to request ligation in the Latin script (and,
less contentiously, the use of ZWNJ to prevent it), many -- including
some experts and UTC members -- have stated that ZWJ should only be used
in exceptional circumstances, or when the requested ligature is
necessary grammatically or orthographically instead of stylistically
(however that is determined).

I'm starting to see why I disagree so strongly with this position. It's
not that I'm eager to "pepper" my text with ZWJs or to require other
writers to do the same, or even that I think modern English text in most
circumstances really requires much more than the basic f-ligatures.

No, what bothers me is that the ZWJ/ZWNJ ligation scheme is starting to
look just like the DOA (deprecated on arrival) Plane 14 language tags.
In each case, Unicode has created a mechanism to solve a genuine (if
limited) need, but then told us -- officially or unofficially -- that we
should not use it, or that it is "reserved for use with special
protocols" which are never defined or mentioned again.

I think I've lost the battle regarding Plane 14 tags -- though I can't
promise I'll never use them in plain text without those mysterious
"special protocols" -- but the fight for ZWJ ligation continues.

The UTC may have "intended" that ZWJ ligation be used only in rare and
exceptional circumstances, but UAX #27, revised section 13.2 doesn't say
that. It says that ZWJ and ZWNJ *may be used* to request ligation or
non-ligation, and that "font vendors should add ZWJ to their ligature
mapping tables as appropriate." It does acknowledge that some fonts
won't (or shouldn't) include glyphs for every possible ligature, and
never claims that they must (or should). It specifically does *not* say
that ZWJ ligation is to be restricted to certain orthographies, or to
cases where ligation changes the meaning of the text.

As Michael and Asmus have pointed out, without ZWJ ligation we will
continue to see numerous, very serious proposals to add more ligated
presentation forms to Unicode. Is that what we want? Not everyone will
buy into the notion that AAT and OpenType will automagically handle all
ligation scenarios.

ZWJ/ZWNJ for ligation control is part of Unicode. It is not always the
best solution, but it is *a* solution, and should be available to the
user without restriction or discouragement.

-Doug Ewell
 Fullerton, California

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