Below is a case study in ASL phonological acquisition from cooing and babbling to utterance of a bilingual child "Juli" whose first language is ASL (American Sign Language) in a ASL native environment.
Note that each child acquires at different rates and develops in different ways. But, the chart gives a general idea of the ASL phonological development of a child. Note that in spoken English, there are about 40-44 phonemes and an English-speaking child completes all phonemes at about 7-8 years old. It seems to be no different from a child acquiring all ASL primes within a similar age range.
The first prime of the unmarked handshape "5" or open handshape appeared. Juli made coos with her open handshape. It parallels to spoken cooing.
Batting movement -- moving up and down repeatedly and simultaneously -- emerged at 5 months.
The handshape prime "1" (or "G" in linguistic term) emerged, but it's used for non-linguistic gestural pointing, not found in ASL words.
Gestural pointing emerges at this stage in both children who are never exposed to sign language and other children who are born to signing families.
Alternating, when batting or tapping with her arms/hands, emerged. This babbling skill later applied to producing drive-car down the road.
The "A" handshape prime began to form as seen in apple/orange, drive-car, bath, strawberry, and some other ASL words.
Juli formed from the "5" handshape into the "A" handshape in work, her earliest and first babble.
This approximate baby O handshape emerged at about 13 months. Juli used it in glasses (two-handed on head), cow, eat, water, later moon, and so on.
The original "baby O" handshape began to form into the 0-flat handshape at 14 months as in eat and more which both are then produced perfectly.
The movement "cradling" as in baby emerged.
The movement forward once as in fish emerged.
Juli had been using the "1" handshape prime in gestural pointing only (non-linguistic gesture), but not in ASL words, until late 15 months. The linguistic "1" handshape began to emerge, as found in pineapple, hurt, cry, comb, etc.
Movement parameter: Juli began to coordinate her arms in a circular motion as in bicycle and top (turning toy).
Interesting, in parallel in her physical development, Juli could draw imperfect circles and she was able to unscrew a toothpaste cap.
The palm orientation and movement began to rotate from the horizontal to the vertical level as found in jumping.
The babbling handshape R began to form, then disappeared or unused. Reappeared a bit later when naming the letter R at 21 months.
Juli knew a subtle difference of the movement between rain and snow. She produced them with the correct movement.
Before Juli used to produce flower below the nose, but now she produced it correctly on the nose (location parameter).
Juli now produced the ASL word star almost perfectly with the correct "1" handshape. In the past months, she used the "A" handshape when signing star.
Juli produced dirty on the correct chin location. She used to raise her elbow with the handshape in mid-air. (a good example of proximilization)
Formed the handshape "C" well for ball rather than the open or flat hand. The production "boy" was well-formed.
Produced pet/petting on her base/passive hand. It used to be one-handed in neutral space.
Juli began to practice naming the alphabetical letters. Juli produced the letter Z with an approximate zig-zag movement.
Formed the alphabetical letter R comfortably. But, this handshape is not integrated with some ASL words such as "rocket" yet, only the letter R as a standalone.
Produced waggling-tail using two-handed (with the dominance condition) -- the use of the right-handed elbow with the left-handed base hand.
Formed the handshape "O", "B" (with the thumb inside), then "D" and then "X" as standalone, but some of them hadn't been incorporated into ASL signs.
Exhibited facial expression (affective) incorporated with ASL signs, such as "sad".
Not only Juli was able to form the handshape "W", but also she could incorporate it into an ASL word/sign water. She struggled with forming the handshape "F".
The handshapes "U" and "V" appeared in some ASL signs such as jump, but she still couldn't produce them as alphabetical letters or standalone handshapes.
Juli accurately produced the ASL word/sign firefighter with the correct palm orientation (palm facing forward) and the handshape "B" (with the thumb inside).
Juli first incorporated the handshape R into an ASL word/sign rocket.
Then next month, Juli used the handshape "R" in many ASL words that contain the handshape "U" and "V", even though she knew the difference between R and U / V handshapes. The handshape R helped her transition from R to U and V in ASL words (to keep the ring finger and pinkie down).
When attempting to form the handshape "F", she used the handshape "W" as found in cat, fox, and later earth and many other signed words.
First used the thumb when producing either mother or father with the correct handshape "5" and fine (thumb touched on the chest).
Not only she could wiggle her thumb in turtle, but she also began to form the handshape "T". Both required the ability to control the thumb.
Successfully formed the handshape "U" in ASL words such as sit, train, uncle. The handshape "U" was still used for "V" in ASL signs with the "V" handshapes.
Used the "W" handshape in replacement of "F" in ASL words/signs cat, fox, First Nations, and such.
Also used the "W" handshape (handshape error) for "open 8" handshape as in sick and for the handshape ILY in airplane and ILY.
Changed from the handshape "1" to "A" for juice. Why the handshape "A"? Maybe this handshape "A" is the closest to the handshape "J". Sooner or later, her little pinkie would pop up to make a "J".
Formed the handshape "2-bent" as seen in entertainment-fair, sled, potato and cherry (European region).
The handshape "V" appeared to be mature that Juli comfortably formed it in her ASL words, such as stand.
However, Juli couldn't form this handshape "V" as a standalone for the ASL cardinal number "two". This handshape "2" can be found in ASL words or signs, not in its standalone handshape.
Juli was able to cross her arms on her chest as in bear and love.
The handshape "K" or "P" (both same handshape but different orientation) began to emerge as seen in park.
The movement in park and video also developed to a more circular.
The handshape "4" emerged in ASL number "four".
The handshape T emerged as in #TV and toilet. She was getting close to "V" (or "2") when producing TV.
The handshape ILY emerged as in ILY, camping, and airplane.
Then later, Juli successfully formed the handshape Y at ease as in yellow, later stay and now.
Successfully formed the handshape I without the support of T. She produced drawing perfectly with the right "I" handshape.
Formed the handshape F in some ASL signs such as find and tea.
Played with the handshape L. Formed the marked handshape E as found in easter and fs-ferret (fingerspelling).
Comfortably formed the handshape F whenever producing cat and some time later fruit.
Formed the handshape 3 when producing three and three-us.
Juli was able to form handshape 3-claw as in dinosaur, but I don't know when it first emerged.
The handshape K or P formed perfectly as in #BOOK and #PEPPA.
Juli could form the handshapes 7 and 8 as standalone but couldn't incorporate them in counting from six to ten nor in ASL signs.
Produced butterfly perfectly with the right handshape, palm orientation, and location.
Incorporated the "8" handshape into ASL signs: silver.
Her phonological productions is generally mature in ASL signing. A few notes of phonological development at this age.
When signing "advertise/ed/ment", instead of tapping her dominant "S" handshape on passive "S" handshape, she tapped her dominant "S" on her arm near elbow (proximalization).
The handshape "8" is one of the most difficult and one of the last handshapes to develop. At this age, she comfortably uses this handshape in ASL signs, but when counting up to 100, it requires her to concentrate any 7 and 8 in numbers such as 17, 18, 27, 28, and so on.
To be continued. This DRAFT chart is a work in progress.
For more information on the acquisition of handshape.
Boyes-Braem, P. (1973/1990). Acquisition of the handshape in American Sign Language. In V. Volterra & C. J. Erting (Eds.), From gesture to language in hearing and deaf children (pp. 107-127). New York: Springer-Verlag.
Also see phonological acquisition with handshapes language acquisition in ASL.
This documentation project follows a baby's language acquisition, literacy development, and phonological acquisition in sign language, specifically ASL, week by week from gazing at birth to manual babbling, to first words just before the first birthday in a natural native-ASL environment and visual culture.
The second-year and third-year documentation continues to follow the same child's language and phonological acquisition and literacy development in ASL on a weekly basis from the one-word stage to two-word and multiple utterances.
The documentary continues to follow the same child's ASL language and literacy development on a regular basis from age three to four. It surveys ASL phonological acquisition and more complex utterances.
These posts on ASL-English bilingualism, language acquisition, and bilingual education may be of an interest for parents who raise a bilingual-bimodal child in ASL (or another signed language) and English (or another written and/or spoken language of its respective) as well as informative and educational for ASL specialists, educators, and professionals.