drphil:
Yes there is a sign for "Subway" both the transit system, and the restaurant (and the signs are different, in most areas). Of course, "foot long" is just signed - utilizing 3D space "sandwich, how long? 1 foot"
DDU however was making yet another juvenile anatomical joke ... (only funny if your brain is stuck in middle/high school)
Regarding ASL dictionaries and vocabulary - since it's something that you (drphil) and many others have posted on a number of times...
One thing that many people are unaware of, espeically those who aren't fluent (or working towards fluency) in a Signed Language (ASL, BSL, etc) is that sign language dictionaries only provide the BASIC signs used in that sign language - unlike English/French/German language dictionaries which provide the vast majority of official words (and they forms) of that language. The best way to explain it - is that ASL dictionaries are aimed almost entirely at those learning ASL, etc - NOT those who are fluent in the language. Because the dictionaries are designed to help those who are not yet conversationally fluent (or just so), they contain the words(signs) one would need to carry on a general social conversation - similar to the vocabulary you would find if in an English dictionary meant for 5-10year olds from the children's/ juvenile's section of a bookstore.
That being said, Good ASL (print) dictionaries will provide a solid sign foundation for Signs that have a consistent English translation, but often will not contain signs for idioms, metaphors, figures of speech/sign, Sign Names for Restaurants and Stores etc. Pet names/nicknames/cute terms of endearment are also typically not part of ASL dictionaries as many of them (aside from the basic HONEY, SWEETHEART, SWEET, CUTE etc) are more like Name Signs than vocabulary signs (if that makes sense).
New words/signs, espeically for technologies (email, blog, vlog, hardware, software etc) often are very regionalized for the first few years, as such dictionary authors/compilers/publishers often wait until 1 or 2 signs for a specific word/concept become dominate at which point they are added - even then, they often elect to publish a stand alone dictionary on that subject as a supplement to their general ASL dictionary to that users can replace that "section" as needed every few years etc.
It's also worth mentioning that ASL dictionaries function very differently than dictionaries for spoken &written language - not only in the fundamental layout (signs are almost always listed according to their most commonly used English Gloss - NOT by handshape/movement/component of language etc) but also because of the unique way in which Signed Languages address grammar/conjugation etc (how signs are often altered to express: time, space, quantity, velocity, emotion, etc).
In order to make a truly "complete" ASL dictionary - one that would be truly equivalent to a high school/university level English or French dictionary, containing all the "base" signs along with their variants (conjugation, tense etc), as well as regional considerations/inflections ("regionalism" in sign language is akin to a spoken word with multiple correct pronunciations) etc - The text would literally be thousands of pages in length and to be physically manageable would require splitting into 4 or 5 large volumes, which would resemble a multi-volume encyclopaedia, more than a dictionary.
Not only is creating a dictionary such as this a monumental undertaking in turns of compilation, illustration and Glossing/Translation hours that would be tremendously expensive to create and publish, it would also be prohibitively expensive for individuals to purchase privately (so it would only be accessible to private and public libraries, schools/colleges/universities or other institutions. In addition to all of the practical logistics of creating an uber-complete ASL dictionary - most people who use ASL on a regular basis really don't USE ASL (paper) dictionaries for more than an occasional reference as paper illustrations are a less-than-ideal medium for describing a moving language in which the movements of the fingers, hands, arms, torso, head, face, eyes, mouth, cheek etc ALL contribute to the meaning of the sign one uses - and a subtle alteration of any of these can completely change the intended meaning of what is being signed.
For what it's worth, of all the readily available (ie not
Gallaudet University Bookstore/course books or ASL linguistics texts etc) ASL dictionaries out there , I think two of the best ASL dictionaries currently available are
The Random House Webster's Unabridged American Sign Language Dictionary & supplementary subject specific dictionaries (
Law,
Computer,
Religion,
Medical etc) by Elaine Costello and in Canada
The Canadian Dictionary of ASL Charmaine Letourneau C.M.,Carole Sue Bailey & Kathy Dolby
I can understand why some people may think that ASL is very simple/basis and has a limited vocabulary (compared to their native language) espeically if their knowledge of true signed languages (ASL, BSL etc versus manually coded English SEE/MCE etc) is based on the vocabulary found in ASL (paper & video) dictionaries and what they see on the news/tv/movies/web boards etc, learn from "overview" style courses in school/work, from medical professionals who are not fluent in signed language (ASL, BSL, etc not SEE I/II, PSE etc). Unfortunately the most common ways that people learn about sign language, deaf culture, etc provide a less than accurate (or ideal) vision of what they are truly like - in much the same way watching English language movies in the theatre would give someone from another culture a warped image of what "typical English people's lives are like".
Sorry for the essay, I do hope that you (drphil) and others who have pondered the "why do ASL dictionaries has so few words" question, will take the time to read and consider my post.
Hope it helps !