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CSET: American Sign Language study materials
CSET: American Sign Language study resources

CSET: American Sign Language: Language Acquisition and Development in ASL

CSET: American Sign Language · Work through your exam, one topic at a time.

All guide sections

Language Acquisition and Development in ASL

This domain covers how ASL is acquired as a first language, as a second language, and in bilingual contexts, plus what happens when access to language is delayed. Items ask you to sequence milestones, interpret error patterns, and reason about age effects.

First-language milestones

  • Manual babbling appears around 6–10 months in deaf infants (repetitive hand movements without communicative intent), paralleling vocal babbling.
  • First true signs typically appear around 10–13 months; the one-sign stage is followed by a vocabulary spurt.
  • Two-sign combinations emerge around 18–24 months, roughly the same timetable as two-word speech.
  • Grammatical development continues through the preschool years: verb agreement, classifier predicates, and non-manual markers appear gradually and are mastered in stages, with overgeneralization errors such as applying a movement pattern too broadly.

Native versus late exposure

  • Deaf children of Deaf parents (native signers) receive accessible input from birth and follow typical milestones.
  • Deaf children of hearing parents often experience delayed, inconsistent, or inaccessible input; outcomes vary with the age and quality of ASL exposure.
  • Research on age of acquisition shows a sensitive period for syntax and phonology: learners first exposed in adolescence or adulthood can become fluent but typically show persistent differences in complex syntax and morphological processing.

Bilingual and second-language acquisition

  • Many deaf children are bimodal bilinguals (ASL and English print or spoken language); code-blending is normal in bilingual Deaf families.
  • Hearing L2 learners of ASL are typically stronger in vocabulary than in ASL-specific phonology and non-manual grammar; L1 English transfer shows up in word order and fingerspelling dependence.
  • Cochlear implantation does not make ASL unnecessary or harmful; outcomes depend on many factors, and bilingual input is compatible with spoken-language development.

Worked example

A Deaf 4-year-old with hearing parents, no consistent ASL input, produces only single signs and no verb agreement. Reasoning: compare with native-signing norms (4-year-olds produce multi-clause narratives), rule out a cognitive explanation, identify restricted access to language as the primary factor, recommend rich ASL input and assessment in ASL rather than English, and monitor progress over time.

Traps

  • Equating sign language exposure with delayed speech (it does not cause speech delay).
  • Blaming ASL for weak English literacy.
  • Oversimplifying the critical period as a hard cutoff at one age.
  • Treating manual babbling as imitation rather than linguistic development.
  • Assuming all deaf children share one acquisition profile.