Lars,

Well, I like that subject and I will try to give a reflexion with
my understanding. I think that I have written a litle like what
William Bright has suggested.

[you wrote]

> Maybe. The question is, what does that mean? Do we have a definition
> of the "featural" class that is good enough that we can look at other
> scripts and tell whether or not they too are featural?
>
> I know the definition says that the character shapes "correlate with
> distinctive features of the segments of the language", but I have only
> the faintest idea what that means. What are "segments"? Is it a
> recognized linguistic term? And what are these "features"? Is this a
> linguistic term, or does it just mean "feature" in the dictionary sense?
>
> In short, what is a featural script?
>
> | Which does not, however, mean it represents Jakobsonian distinctive
> | features.
>
> What are they? What is a good place to learn about them?

[mariano]
I will use the term *feature* as equivalent either to *articulatory*
or to *acoustic* feature by wich a phonem may be defined.
I would understand by pure or proper "featural" a writing system
in wich all *phonem* definitory *features* are represented (see below
for more explanation). I would say that a particular individual symbol
is featural if *it represents just one phonemic feature and not a phonem
or if it is a compound, each of the compound elements represents one phonemic
feature and all the features of that wich is represented by the compound
are represented*.
For example: the Japanese <"> is used as symbol for [+voiced] and de <º>
is used somewhat as symbol for [interrupted], so that both are featural
symbols, that I would classify also as diacritics in that case.
If each Japanese symbol were like that, then, Japanese would be a featural
system, but it is a mixed system at least for three properties:

Japanese is a system logographic + syllabary with featural diacritics.

(I use "logographic" as far as I do not know about reasons for another
term).
I think that Han-gul is featural as far as the same symbol may be reused
to make another symbol (for example by doubling it) or a symbol is
used together with anothers to mark a feature (for example for the
aspirated phonems). But it is no featural with respect that there
are symbols that represent by themselves an individual phonem
-what is analogous with the phonemic (or alphabetic) and other
systems- and because not all features are represented.
When a simple (not compoun) symbol represents an individual
phonem it might be better called *phonemic* than *alphabetic*
and if it were known that has iconicity for just one feature, I would
say that it is an abstract iconicity.
In adition, A. the featural symbols of han-gul are not diacritics as they do
not differ from the phonemic symbols, what is a difference with
respect Japanese (and also with respect some of the IPA diacritics and
other systems that have some featural diacritics). B. what is represented
by the han-gul featural as well phonemic symbols are articulatory features
(as for visible speech), whilst for Japanese and some of the IPA what
are represented by the featural symbols are acoustic features. C. han-gul
has a given by its researchers) iconocity for some of the articulatory
that is mainly abstract (or symbolic) for the phonems.

I think (also after reading other these days mails) that Han-gul is
a mainly phonemic - and featural - and sillabic system of symbols with
given articulatory iconicity.

Han-gul might be more "fonemic" than some uses of the latin alphabet and
more or less as "fonemic" as italian, so that fonemicity might be quantified
in the sense of univocity of the relation writen symbol-phonem. But,
as this has to be with the amount of arbitrariness I think it might be also
described as degree of phonemic arbitrariness instead of as a degree
of fonemicity.

About fonemic features:
Fonemic features are defined in two more or less paralelle systems
depending on the kind of property and there may be made a mixed system
of classification with both kind of properties, either 1. articulatory features
or 2. acoustic features.
A set of these acoustic features was defined by Jacobson and have been
used and researched by phonetist along the last decades (I do not know
if it will follow that way). Most use to be defined in pairs, like
[+ continuous] versus [- continuous] (but [- continuous] is equal
to [interrupted]).
These are definitions of *phonetic* features (that is physical sounds)
but also the prototipic features of a range of allophones may be used
to define a phonem (a phonem is the elementary part in wich cognitively
language sounds are segmented as represented in phonemic writing
symbols; whilst an allophone is physic and has a unique physical
actuality a phonem is cognitive and has a range of allophones
as its actuality in physic sound).

If a pure featural writing system were to be made a smaller set of symbols
than for a phonemic (alphabetic) system would be needed, by taking
only the prototipic phonetic features that were relevant for phonem distinction
and defining each phonem by a combination of them.

In addition, most of the writting systems that have been invented (han-gul,
Bell's visible speech, Wilkins visible speech and other) not only
it might not be right to call them pure or proper featural, but also it would
be posible to say that fail in not thinking with the mind of a hearer
(rather are made with the mind of a speaker observing himself). So
that it seems that has been much more easier for researchers to think
about articulatory features than about (Jacobson's like) acoustic features;
but now is much more easier to make spectrograms and, then, I think
it may be expected that in a near future there will be invented writing
systems that will try to represent and be iconic for the acoustic features,
or alternatively will have phonemic abstraction for the acoustic features
(but there could be made also mixed not necessarily excluding
the articulary, but using them secondarilly).
As far as these acoustic features are more relevant than the articulatory
for the brain or mind also it should be expected that for natural writing
systems (those systems that have undertaken changes an evolution
by use from generations along history) might have symbolism
for some acoustic features and even some of the invented systems might
have traces of unexplicited symbolism for the acoustic.

Yours cordially,
mariano