Alive, but, if like me, probably not sure about the exact
nature of the the Tamil sound in question.
As best as I can remember, from the last time I had one of
Bhadriraju Krishnamurti's books in hand, the sound is a
reflex of a Proto-Dravidian voiced apico-alveolar fricative
(written as an underdotted 'z'), but that is not supposed
to be its present realization. The book included varying
descriptions of the modern sound from more than one author,
and I don't remember which one, if any, that Krishnamurthi
If the sound is indeed a "semivocalic (open) counterpart
of the retroflex lateral /L/" then I suppose it could be
written with the I.P.A. as a retroflex lateral approximant
with the diacritic for lowering beneath it.
Refer to the "CONSONANTS (PULMONIC)" table at http://www2.arts.gla.ac.uk/IPA/images/ipachart.gif , where
the "retroflex" column intersects the "lateral approximant"
row, for the symbol for a retroflex lateral, which resembles
an 'l' with a tail descending below the line. The diacritic
for lowering can be found in the tenth row, second column
of the table of diacritics, and looks like the bottom half
of a + sign.
However I wonder, if there's no contact of the tongue with
the roof of the mouth during this sound, whether it's proper
to refer to, or write, it as a lateral of any sort?
I second the request that a native speaker of Tamil upload
a recording of the sound, preferably at normal speed between
two 'a'-s ("aLa"), as well as drawn out ("aLLLLLLLLLLLLa").