First, let’s delve into the TYPICAL LINGUISTIC DEVELOPMENT of young, deaf learners acquiring a sign language. This will provide us with a platform by which we can further examine vocabulary development.
Children acquiring ASL begin to recognize that signs are symbols capable of and important for carrying meaning .
At approximately 6 months of age, children systematically exposed to ASL begin to babble in the manual modality just as hearing children do when systematically exposed to a spoken language [16, 20].
By the age of 12 months, children systematically exposed to ASL begin using their first meaningful sign [2, 20].
The first signs used by children acquiring ASL tend to be nouns .
Between the ages of 1 and 2 years of age, children acquiring a signed language become slightly more proficient in their language use, employing more than 50 signs .
Children begin coupling signs with pointing [2, 10, 13, 18] and forming two-sign combinations .
Additionally, children begin to understand that eye gaze is imperative to give and receive messages , follow simple directions , and sign about things that are present .
Between the ages of 2 and 3 years old, children acquiring a signed language become even more skilled with the language, actively expressing more than 250 signs .
Children at this age begin to use negation words, such as “no,” “none,” and “not-want” .
Children at this age also begin to use fingerspelling [8, 15].
Children at this age begin to express emotions (e.g., signs for happy, sad, mad) .
Children begin to use ASL to figure out how things work, explain games, or even tell stories .
After the age of 3 years old, children acquiring a signed language begin using ASL to share daily experiences and events , to ask and understand questions (e.g., “where,” “how,” and “why”) , and to produce simple sentences (i.e., those including a subject-verb-object structure and some complex sentences) [17, 19].
Children are also able to maintain visual attention for ASL conversations and utilize appropriate interruptions, turn taking, and gaze shifting .
REGARDLESS OF MODALITY, LINGUISTIC DEVELOPMENT IS SIMILAR. Compared to hearing children who acquire spoken language, the developmental milestones of deaf children acquiring a signed language are not deviant. However, materials that simultaneously assess linguistic, including vocabulary, development are scarce. Therefore, for the hearing parent of a deaf child acquiring a sign language, this information as well as information about how to facilitate language vis-à-vis vocabulary development might not be readily available or accessible. Children, when provided more opportunities for communicating with parents, siblings, peers, and other adults, have shown to develop better language skills [6, 12]. Additionally, early exposure to quality language, including vocabulary, is essential for developing appropriate socio-emotional attachment/bonds  and, as stated previously, reading comprehension [3, 4, 5, 14, 21, 23].
We aim to close this gap of understanding by providing EDUCATIONAL MATERIALS in the form of a website and informational handouts catering to professionals who work closely with parents who have deaf or hard-of-hearing children acquiring a sign language, including but not limited to teachers, early interventionists, speech-language pathologist, doctors and clinicians (e.g., pediatricians, audiologists), et cetera. acquiring a signed language. These materials will not only elucidate the similarities between typical spoken and signed language acquisition, but will also provide suggested actions for parents, teachers, and caregivers to facilitate vocabulary development. It is our goal to provide accessible materials that will increase awareness of i) the similarities between spoken and signed language acquisition, ii) the importance of vocabulary development, and iii) some actions that parents, teachers, and caretakers can take in order to facilitate vocabulary development in sign language learners.
Vocabulary is one imperative component of language development, whether the child is hearing and acquiring a spoken language or deaf or hard-of-hearing acquring a signed langauge. In addition to the predictory nature of vocabulary development on reading comprehension, vocabulary size has been correlated with brain function for language processing .
THE BEHAVIORAL ABILITY TO LEARN NEW WORDS based on small distinctions from other words (i.e., fine phonologial and phonemic distinctions) is more closely correlated to vocabulary development than age [26, 32, 33, 34]. This further stresses the importance of vocabulary development and vocabulary skills both on a developmental timeline and a cognitive maturational timeline.
Additionally, research tells us that deaf, native signers exhibit typical brain activity and cognitive processing patterns for sign language as hearing, native speakers do for spoken langauge [27, 29, 30, 31, 35]. However, children must be provided with unimpeded (i.e., modality-appropriate) access to rich language experiences early in life to achieve typical language processing [27, 30]. The urgency on "early-life" unimpeded access to rich language experiences is commonly referred to as the language critical/sensitive window.
View our supplemental materials, which includes tips on building vocabulary in deaf and hard-of-hearing children and a side-by-side timeline for linguistic development in both spoken and signed langauges.
As part of this online resource guide, we have compiled a list of other resources that you might find useful. Please note that this list might not be comprehensive in scope.