Bilingual signed and spoken language acquisition from birth: implications for the mechanisms underlying early bilingual language acquisition
Petitto et al (2001)
- 1. The hand movements of hearing babies under deaf parents
- 2. Found that such children produce a class of hand activity
- distinct from other uses of their hands
- contains the specific rhythmic patterns of natural language ('silent' babbling)
- 3. Two contrasting views on babbling: purely non-linguistic motor activity vs. linguistic activity that reflects babies' sensitivity to specific patterns at the heart of human language and their capacity to use them (particularly, rhythmic patterns)
Experiment
- Participants
- 3 hearing babies (0;6, 0;10, 0;12) who received no systematic exposure to spoken language & saw only signed languages from their deaf parents
- 3 hearing babies who were exposed to spoken language (other things except for the difference of the form of language input (i.e., hand and mouth are controlled)
- Hypothesis: If babies are born with sensitivity to specific rhythmic patterns that are universal to all languages, even signed ones, then the linguistic hypothesis predicts that differences in the form of language input should yield differences in the hand activities of the two groups.
- cf. hearing babies only with hand input -> their hand activity should be similar to that of hearing babies acquiring spoken language because they do not use their mouth and jaw to learn speech
- Equipment: 3 dimensions using Opotrak, position-tracking system
- Results:
- sign-exposed babies showing different type of low-frequency rhythmic hand activity from speech-exposed babies
- another type of high-frequency rhythmic hand activity that speech-exposed babies also showed and used almost exclusively (Fig. 1)
