D The fourth letter in the English alphabet occupies the
same position in the Latin, Greek and Phoenician
alphabets, which represent the preceding stages in its
history. The Phoenician name Daleth is represented
by the Greek Delta. In form D has varied throughout its career
comparatively little. In the earliest Phoenician it is 
with
slight variations; in most Greek dialects 
which has been
adopted as the Greek literary form, but in others as e.g. the
earliest Attic 
or 
. The form with the rounded back, which
has passed from Latin into the languages of western Europe,
was borrowed from the Greeks of S.W. Italy, but is widely
spread also amongst the peoples of the Peloponnese and of
northern Greece. It arises from a form like 
when the sides
which meet to the right are written or engraved at one stroke.
From a very early period one side of the triangle was often
prolonged, thus producing a form 
which is characteristic of
Aramaic from 800 B.C. In Greek this was avoided because of
the likelihood of its confusion with 
, the oldest form of the
symbol for r, but in the alphabets of Italy—which were borrowed
from Etruscan—this confusion actually takes place. Etruscan
had no sound corresponding to the symbol D (in inscriptions
written from right to left, 
), and hence used it as a by-form
for , the symbol for r. The Oscans and Umbrians took it over
in this value, but having the sound d they used for it the symbol
for r ( in Umbrian, 
in Oscan).
The sound which D represents is the voiced dental corresponding
to the unvoiced t. The English d, however, is not a true
dental, but is really pronounced by placing the tongue against
the sockets of the teeth, not the teeth themselves. It thus
differs from the d of French and German, and in phonetic terminology
is called an alveolar. In the languages of India where
both true dentals and alveolars are found, the English d is
represented by the alveolar symbol (transliterated ḍ). Etymologically
in genuine English words d represents in most cases
dh of the original Indo-European language, but in some cases
an original t. In many languages d develops an aspirate after it,
and this dh becomes then a voiced spirant (ð), the initial sound
of there and that. This has occurred widely in Semitic, and is
found also in languages like modern Greek, where δ, except after
ν, is always spirant, δέν (= not) being pronounced like English
then. As the mouth position for l differs from that for d only by
the breath being allowed to escape past one or both sides of
the tongue, confusion has arisen in many languages between
d and l, the best-known being cases like the Latin lacrima as
compared with the Greek δάκ–ρυ. The English tear and the
forms of other languages show that d and not l is the more
original sound. Between vowels in the ancient Umbrian d
passed into a sound which was transliterated in the Latin
alphabet by rs; this was probably a sibilant r, like the Bohemian
ř. In many languages it is unvoiced at the end of words, thus
becoming almost or altogether identical with t. As an abbreviation
it is used in Latin for the praenomen Decimus, and under
the empire for the title Divus of certain deceased emperors.
As a Roman numeral (= 500) it is only the half of the old symbol
(= 1000); this was itself the old form of the Greek φ, which
was useless in Latin as that language had no sound identical
with the Greek φ.
(P. Gi.)