5.1 ASL Phonological Structure & the Five Parameters

Core Principle: American Sign Language (ASL) possesses a fully developed, rule-governed phonological system composed of meaningless, contrastive sublexical units that combine systematically to form meaningful morphemes, disproving historical misconceptions of sign language as mere gesture or pantomime.

For more than two centuries, mainstream educational and academic institutions viewed sign language through an audist and pathological lens, dismissing visual-spatial communication as primitive pantomime, iconic pictorial gesturing, or a broken derivative of spoken English. This pervasive myth was dismantled through empirical linguistic research, demonstrating that sign languages are autonomous, natural human languages exhibiting the full spectrum of universal linguistic properties—beginning with a rule-governed phonological system.

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1. Historical Development: William Stokoe's 1960 Breakthrough

In 1960, William C. Stokoe Jr., an English professor at Gallaudet College (now Gallaudet University), published a landmark monograph titled Sign Language Structure: An Outline of the Visual Communication Systems of the American Deaf. Stokoe applied structural linguistic principles to the signing of Deaf Gallaudet students and faculty, demonstrating that ASL signs are not indivisible pictorial gestures. Instead, every sign is composed of distinct, meaningless sublexical building blocks that combine according to rigorous phonotactic constraints.

Cherology: The Birth of Sign Language Phonology

Because the term "phonology" historically derived from the Greek phone (sound or voice), Stokoe coined the term cherology (from the Greek cheir, meaning hand) to describe the visual-gestural equivalent of acoustic phonology. The meaningless contrastive units that make up signs were termed cheremes (analogous to spoken phonemes). While modern linguistics has harmonized terminology to use "phonology" and "phonemes" across both signed and spoken modalities, Stokoe's cherological framework provided the foundational architecture for all subsequent sign linguistics.

In his 1965 Dictionary of American Sign Language on Linguistic Principles (co-authored with Carl Croneberg and Dorothy Casterline), Stokoe formalized the first linguistic notation system for ASL based on three simultaneous parameters:

1. TAB (Tabula / Location): The place on the body or in neutral space where the sign is articulated (e.g., forehead, cheek, chin, chest, trunk, or neutral space in front of the torso).
2. DEZ (Designator / Handshape): The specific configuration of the hand and fingers used to produce the sign (Stokoe identified 19 distinct handshape configurations, such as the flat hand, the fist, the index finger, and the spread hand).
3. SIG (Signation / Movement): The action or movement executed by the hand(s) (e.g., upward, downward, circular, twisting, tapping, or oscillating).

+-----------------------------------------------------------------------------------+
|              Stokoe's Original Cherological Model of ASL (1960)                   |
+-----------------------+-------------------------+---------------------------------+
|     TAB (Tabula)      |     DEZ (Designator)    |        SIG (Signation)          |
|   Location / Place    |     Handshape / Hand    |       Movement / Action         |
+-----------------------+-------------------------+---------------------------------+
| Where the sign occurs | Configuration of hand   | Motion executed by active hand  |
| (Forehead, Chin, etc.)| (Fist, Index, Flat-B)   | (Tapping, Circular, Arc, Twist) |
+-----------------------+-------------------------+---------------------------------+

Simultaneity vs. Sequentiality

A major theoretical breakthrough of Stokoe's model was identifying the contrast between spoken and visual language transmission. While spoken language phonology is primarily sequential (phonemes follow one another in a linear acoustic stream over time: /k/ - /æ/ - /t/), ASL phonology is predominantly simultaneous. In Stokoe's formulation, TAB, DEZ, and SIG are produced simultaneously at a single point in time. Although later researchers (notably Scott Liddell and Robert Johnson in their Movement-Hold Model) demonstrated that ASL signs also possess sequential segments (Movements and Holds), Stokoe's demonstration of simultaneous sublexical architecture remains the bedrock of sign linguistics.

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2. Expansion to the Five Parameters of ASL

As sign linguistics matured throughout the 1970s and 1980s, researchers recognized that Stokoe's three-parameter system could not fully account for all minimal distinctions in the ASL lexicon. Linguist Robbin Battison (1978), in his groundbreaking work Lexical Borrowing in American Sign Language, demonstrated that the spatial orientation of the palm functions as an independent, contrastive parameter. Concurrently, researchers including Charlotte Baker-Shenk, Dennis Cokely, and Scott Liddell proved that non-manual signals convey vital lexical and grammatical contrasts. Today, ASL phonology is universally taught and analyzed through five core parameters.

1. Handshape (DEZ)

The physical configuration of the active fingers and thumb. ASL utilizes dozens of distinct handshapes (often identified by alphanumeric labels corresponding to manual alphabet or number configurations, such as 1, A, B, C, 5, flat-O, bent-V, open-8). Variations in finger extension, flexion at the knuckles, and thumb positioning serve contrastive functions.

2. Location (TAB)

The specific anatomical site on the signer's body or the coordinate region in signing space where the sign is initiated, articulated, or terminated. Major location zones include the head (forehead, eyes, nose, cheeks, mouth, chin), the torso (neck, shoulders, chest, abdomen), the non-dominant arm/hand, and neutral space (the three-dimensional area directly in front of the signer's torso).

3. Movement (SIG)

The kinetic path and dynamic manner executed by the hand(s). Movement can be straight, arched, circular, zigzag, oscillating, twisting, nodding, or contact-based (striking, brushing, tapping, grasping). Movement also incorporates speed, tension, and rhythmic acceleration.

4. Palm Orientation (ORI)

The direction in which the palm, fingertips, or knuckles are directed relative to the signer's body, the interlocutor, or the ground (e.g., palm facing inward toward the chest, outward toward the viewer, upward toward the ceiling, downward toward the floor, or contralateral/ipsilateral).

5. Non-Manual Signals / Markers (NMS / NMM)

Contrastive linguistic behaviors produced by the face, head, and upper torso that co-occur with manual signs. NMS includes eyebrow position (furrowed for WH-questions, raised for yes/no questions and conditionals), eye aperture (squinted vs widened), eye gaze direction, nose wrinkling, mouth morphemes (specific configurations of the lips, tongue, and cheeks), head tilt, head nodding/shaking, and shoulder shifting. At the phonological level, NMS serves a lexical contrastive function, distinguishing otherwise identical manual signs.

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3. Minimal Pairs in ASL

In spoken linguistics, a minimal pair consists of two words that differ by only a single phoneme, proving that the contrasting phoneme carries meaning-differentiating capability (e.g., "pat" vs "bat" differing solely in the voicing of the initial bilabial stop). In ASL, a minimal pair consists of two distinct signs that share four parameters identically and differ in only one parameter.

Demonstrating minimal pairs across each of the five parameters proves that all five elements are phonologically contrastive units rather than stylistic variations.

Minimal Pair Contrasts by Parameter

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4. Phonological Constraints in ASL (Battison 1978)

In natural languages, sounds and gestures cannot be combined randomly; they must adhere to phonotactic constraints that govern well-formed utterances. In spoken English, for instance, a syllable may begin with /spr/ ("spring") but cannot begin with /ŋ/ or /tl/. In ASL, Robbin Battison (1978) formulated two foundational phonological constraints governing the structure of two-handed signs: the Symmetry Condition and the Dominance Condition.

The Symmetry Condition

Rule: If both hands move independently during the articulation of a sign, both hands must have identical handshapes, occupy identical or symmetrical locations, and execute symmetrical movement paths (either simultaneous or alternating mirror-image movements).

• Application: In signs such as PLAY, MAYBE, BICYCLE, SINCE, CAN, and EXCHANGE, both hands are active. Under the Symmetry Condition:
  • Both hands must assume the exact same handshape (e.g., both hands form Y in PLAY; both hands form flat-B in MAYBE).
  • The movement must be symmetrical (e.g., both hands twist simultaneously, or alternate rhythmically as in BICYCLE).
  • It is phonologically impossible in standard ASL to have a sign where the dominant hand executes an S handshape moving in a circle while the non-dominant hand simultaneously executes an active 5 handshape moving in a zigzag.

The Dominance Condition

Rule: If only one hand moves in a two-handed sign (the dominant hand executes movement while the non-dominant hand acts as a passive base), the non-dominant hand must remain stationary and can ONLY assume one of seven "unmarked" (maximally natural) handshapes: B, A, S, O, C, 1 (G), and 5.

+-----------------------------------------------------------------------------------+
|              Battison's Unmarked Handshape Set for Base Hands                     |
|                               [B - A - S - O - C - 1 - 5]                         |
+----------+------------------------------------------------------------------------+
| Handshape| Exemplary Two-Handed Dominance Signs                                   |
+----------+------------------------------------------------------------------------+
|    B     | WRITE (dominant pinch on base flat-B), TABLE, LAW, PAGE                |
|    A     | REMEMBER (dominant A contacts base A thumb), PATIENT                   |
|    S     | BASEBALL (both hands clasp), KEY (twisting on S-fist)                  |
|    O     | TEACH (initiating near temple), MONEY (tapping base flat-O)            |
|    C     | COOKIE (dominant C twists on base flat palm/C)                         |
|    1     | WORD (dominant G/1 taps base index finger), SPECIAL, DISCUSS          |
|    5     | TREE (dominant elbow rests on base flat-5 arm/palm), AGAIN             |
+----------+------------------------------------------------------------------------+

• Linguistic Rationale: Unmarked handshapes are the first handshapes acquired by deaf infants during natural language acquisition, are motorically the easiest to produce, and are universally present across all documented sign languages worldwide. Highly marked handshapes (such as 7, 8, R, X, T, or K) require complex neuromuscular coordination and are phonologically prohibited from serving as an inert, passive base hand.

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5. Phonological Processes in Connected Discourse

When signs are articulated in isolation (citation form), their phonological parameters are crisp, distinct, and complete. However, in continuous natural discourse, signs interact with adjacent signs, undergoing systematic phonological processes to maximize articulatory ease and cognitive efficiency without sacrificing communicative clarity.

1. Assimilation

Assimilation occurs when a phonological parameter of one sign shifts to become more similar to or identical with the parameter of a preceding or following sign.

• Regressive (Anticipatory) Assimilation: The active handshape or location anticipates the upcoming sign. For example, in the phrase ME KNOW, the citation form of ME is an extended 1 index finger touching the chest. When immediately preceding KNOW (which uses a bent-B handshape at the temple), the signer's hand often transitions into a bent-B configuration while contacting the chest, anticipating KNOW.
• Progressive (Perseverative) Assimilation: A parameter from a preceding sign persists into the subsequent sign. For instance, in REMEMBER, the dominant hand retains the A handshape derived from the forehead touch as it contacts the base hand.

2. Movement Epenthesis

When two signs produced at different spatial locations are uttered in sequence, the articulatory system must travel across the intervening physical space. The insertion of a transitional movement between the terminal location of Sign A and the initial location of Sign B is called movement epenthesis. In the sequence FATHER WANT, an epenthetic diagonal movement smoothly carries the hand from the forehead (location of FATHER) downward into neutral space in front of the chest (location of WANT).

3. Metathesis

Metathesis is the phonological reordering of sequential segments or locations within a sign where the lexical meaning remains completely identical. The most famous example in ASL is the sign DEAF:

• In citation form, DEAF is articulated by touching the index finger to the cheek near the ear, then moving to the cheek near the mouth (ear-to-mouth).
• In connected discourse, signers frequently produce DEAF starting near the mouth and moving to the ear (mouth-to-ear).
• Both variants are phonologically acceptable and semantically equivalent. Other signs that undergo metathesis include CONGRESS, FLOWER, HONEYMOON, and NAVY.

4. Hold Deletion (Reduction)

In citation form, many signs terminate in a stationary "hold" (a brief cessation of movement where handshape and location are stabilized). In fast conversational signing, holds between signs are routinely eliminated (deleted) to create fluid, uninterrupted transitions, reducing the sign to its dynamic movement trajectory.

5. Weak Hand Deletion (Weak Hand Drop)

In two-handed signs that adhere to the Symmetry Condition and are produced in neutral space without contact on the body, signers in casual registers frequently omit (drop) the non-dominant hand entirely, producing the sign using only the dominant hand (e.g., CAT, HORSE, COW, TIRED, CAN). However, if the sign requires contact between the two hands or if the non-dominant hand serves as an obligatory base (as in WRITE or TABLE), weak hand deletion is ungrammatical.