mouth morphemes in ASL
ASL> non-manual markers (NMMs) > facial grammar > mouth morphemes
A mouth morpheme is a type of signal or non-manual marker used in American Sign Language and other visual languages to convey information and/or add grammatical information to signs.
By forming your mouth into certain shapes you can create specific meanings or you can combine the mouth shapes with certain signs influence the meaning of those signs.
When you use the movement or shape of your mouth (and/or the tongue) to visually create meaning or influence the meaning of a word or sign you are using a "mouth morpheme."
For example, a "smile" is the meaningful movement of the mouth into a crescent shape that expresses the meaning that the person doing the smiling is pleased or happy.
A smile is not a "word."
A smile is not a sign.
A smile is a signal that conveys meaning and is done without use of the hands.
When something is done without using the hands we refer to that as "non-manual."
A smile is a non-manual signal that carries meaning.
Definition: morpheme: "minimal meaningful language unit; it can't be divided into smaller meaningful units" (Source: "morpheme." Memidex Dictionary/Thesaurus. Web. 6 Feb 2020 <http://www.memidex.com/morpheme>.)
Since a "smile" (when used as part of language**) meets the definition of being a morpheme we can refer to a smile as being a "non-manual morpheme."
Morpheme: A morpheme is the smallest unit of language you can divide into and still carry meaning. When people who study language (linguists) examine words or signs they like to break the words or signs down into smaller and smaller parts. Words (generally) carry meaning. Often you can break a word (or sign) into parts and those parts each have their own meaning. A word or part of a word that still carries meaning but can't be broken down any smaller is a "morpheme."
The word "dog" is a morpheme meaning that hairy thing running around on four legs and stealing your food when it can.
The word "dogs" is made up from two parts: "dog" + "s." Each part has meaning. Each part is a morpheme.The letter "s," when added to dog means there are two or more dogs.
"Dog" is a free (as in freestanding or can stand alone) morpheme and functions as word. The suffix "-s" is a bound morpheme and cannot stand alone.
Since the suffix "-s" cannot stand alone, we call "-s" a "bound morpheme" (because it has to be "bound" to another morpheme to have meaning).
If you break a morpheme into even smaller parts until you can't break the parts any smaller and those parts lose their meaning they are called phonemes. For example, the word "dog" is a morpheme. If you break dog into its parts (d), (o), (g) -- you now have three phonemes that by themselves are meaningless.
Or look at it this way: The letters "g," "d," and "o" cannot be broken down any smaller and still be considered units or parts of English.* By themselves, unorganized, and without context the letters "g," "d," and "o" are meaningless and are considered phonemes.
(* In regard to the letters "g," "d," and "o" -- yes, yes, sure, you could break the "o" in half down the middle and call the left half a "c" or you could break the "d" into an "o" and an "l." Ha, ha, you clever person you! Yay! Clap, clap. Now, focus.)
If we take the phonemes "g," "d," and "o" -- and we give them context by organizing them into "dog" (or "god") we have built a morpheme out of phonemes.
"S" when bound to the end of "dog" has meaning. It is a "bound morpheme."
"S" floating around on its lonesome is meaningless. When "s" is out of context we call it a phoneme.
Free morpheme: dog
Bound morpheme: -s (can have meaning when attached to an other morpheme)
Phoneme: s (out of context = meaningless)
Meaningless pair of phonemes: og
Phonemes combined into a freestanding morpheme that is also a word: go
** The spoken English word "smile" is only a morpheme when it is used as part of a language. If a parrot hears the word "smile" and repeats the word smile in-between squawks it would be hard to defend the idea that the bird is using the word smile as a morpheme (a minimal meaningful unit of language). Taken to an extreme -- suppose we set a computer to make random noises and string them together. After a billion or so random noises suppose the computer's speaker produces a series of sounds that sound like the word "smile." Would it be accurate to suddenly exclaim that the computer is using language and wants you to smile? (No, it would not.) Intent and inference are what change images and sounds from noise into signs and words.
Statement 1: A person can smile in a non-morphemic way. (Example, asleep / dreaming).
Statement 2: Similarly a collection of sounds that "sound like" the word "smile" can occur in a non-morphemic way.
Neither of those two statements takes away from the fact that a person can also use a smile as a morpheme.