In everyday life with everyday people if for some reason your
signing partner needs to express the concept of "letter" as in
"a letter of the alphabet," there is more than a small chance
that he or she will do the sign for "letter" as in a piece of
mail. (See: "LETTER-(mail).")
It is also likely the "LETTER-(mail)" sign used will be a
version in which both the dominant and non-dominant hands are in
"A" handshapes. This is a natural evolution of the citation form
of the sign in which the non-dominant hand is a "flat-hand" (or
a "B"-hand) wherein the flat hand represents an envelope and the
dominant "A"-hand represents the placing of a "stamp" onto an
envelope.
I'm not going to debate the right or wrongness of using a
version of the "LETTER-(mail)" sign to mean
"LETTER-of-the-alphabet)." Whether it is wrong or right is
simply a question of "Does a substantial number of native Deaf
adult members of the Deaf Community recognize and use the sign."
What I will do here however is show you a specialized
sign that may be helpful for English classrooms. By "English
classrooms" I mean Deaf Education environments in which Deaf
students are studying English. In such classes the teacher
and students may find it useful to have a sign which clearly and
specifically refers to a "letter of the alphabet" rather than "a
piece of mail."
For that purpose there is an initialized sign based on
the sign for
"word"
wherein you do the sign
WORD but you swap out the regular
"G" dominant handshape for an "L" handshape.
To sign "letter" touch the tip of the thumb of the dominant "L" hand to the tip of the
non-dominant index
finger. Use a small double motion. The non-dominant hand stays stationary, the
dominant
hand moves.
LETTER-of alphabet:




See: LETTER-(mail)