Children's Contribution to the Birth of Nicaraguan Sign Language

Ann Senghas

The present study examines children's ability to create grammatical structure. A new language has emerged in the hands of a generation of deaf children in Nicaragua. This study examines some of the specific constructions that have emerged in this new signed language in order to determine whether the language is indeed changing over time, and whether the changes in the language originate in older or younger signers.

A nonverbal cartoon was presented to deaf Nicaraguan signers to elicit topic-controlled narratives. Morphological differences between the narratives were examined with respect to the signers' Age at Entry into the signing community, and the signers' Year of Entry into the signing community.

The age at which signers first enter the Nicaraguan signing community predicts their ultimate ability to command some of its more complex structures. Signers who arrived at a young age produce more complex, multi-morphemic signs and use the inflectional and verb agreement system more than signers who entered the community at an older age. These findings are consistent with theories that claim that children*s language-learning abilities decrease with age.

When the effect of Age at Entry is controlled for, a higher prevalence of these same complex constructions among signers with a later Year of Entry indicates a richer signing environment at the time of learning, thus demonstrating that the language has become more complex over recent years.

This effect of Year of Entry is present only in the signers who entered the community under the age of ten. Thus, the new developments in the language originate in the youngest children in the community. As they apply their natural language acquisition capacity to the nonnativized, incomplete input that surrounds them, they generate a rich and structured grammar, which becomes measurably richer with each passing year.

Thesis Supervisor: Steven Pinker
Title: Professor of Brain and Cognitive Sciences

Table of Contents

1. Introduction 13
1.1. Theoretical considerations 15
1.2. The Nicaraguan Sign Language Project 17
1.3. The structure of the thesis 18

2. Evidence of Enrichment 21
2.1. Cases of language deprivation 21
2.1.1. Feral children 22
2.1.2. Genie 23
2.1.3. Deaf children with hearing parents 24
2.1.4. Isabelle 26
2.1.5. Children exposed to pidgin language 27
2.1.6. Learners exposed to language after early childhood 29
2.1.7. Deaf children surrounded by non-native models of ASL 32
2.1.8. Simon 33
2.1.9. Language learning in a rich environment 34
2.1.10. Discussion 35
2.2. The emergence of Nicaraguan Sign Language 36
2.2.1. History of the community 36
2.2.2. The development of the language 36
2.3. Comparison to the earlier cases 38

3. Study I: A Comparison of Older and Younger Signers 41
3.1. Introduction 41
3.2. Measures 41
3.2.1. General measures of fluency 42
3.2.2. Mimetic signing 43
3.2.3. Verbal spatial inflection 45
3.2.4. Classifiers and specifiers 47
3.2.5. The prevalence of forms 52
3.3. Method 53
3.3.1. Subjects 53
3.3.2. Materials 53
3.3.3. Procedure 54
3.3.4. Coding and analyses 54
3.4. Results 55
3.4.1. General measures of fluency 55
3.4.1.2. Morphemes per minute 55
3.4.1.3. Morphemes per sign 56
3.4.1.4. Mimetic signing 57
3.4.2. Verbal inflection 58
3.4.2.1. Position/location inflection 58
3.4.2.2. Person inflection 59
3.4.2.3. Number inflection 60
3.4.3. Classifiers and specifiers 61
3.4.3.1. Object (semantic) classifiers 61
3.4.3.2. Handling classifiers 62
3.4.3.3. Size and shape specifiers 63
3.5. Discussion 64

4. Study II: The effects of age and year of entry on verbal inflection 69
4.1. Introduction 69
4.1.1. Age at Entry 70
4.1.2. Year of Entry 70
4.2. Measures 71
4.2.1. Measures from Study One 71
4.2.2. Additional measures 72
4.2.2.1. Shoulder shift 72
4.2.2.2. Aspectual markers 72
4.2.2.3. Agreement 73
4.2.2.4. Verb phrase complexity 74
4.3. Predictions 75
4.4. Method 75
4.4.1. Subjects 75
4.4.2. Materials 77
4.4.3. Procedure 77
4.4.4. Coding 77
4.4.5. Analyses 78
4.5. Results 79
4.5.1. General measures of fluency 79
4.5.1.1. Morphemes per minute 79
4.5.1.2. Morphemes per sign 85
4.5.2. Verbal Inflection 88
4.5.2.1. Position/location inflection 88
4.5.2.2. Person inflection 91
4.5.2.3. Shoulder shift 94
4.5.2.4. Aspectual inflection 96
4.5.2.5. Total inflections per verb 99
4.5.3. Verbal agreement 102
4.5.3.1. Position/location agreement 102
4.5.3.2. Person agreement 106
4.5.3.3. Total agreement per verb 109
4.5.4. Verb phrase complexity 112
4.5.4.1. Arguments per verb 112
4.5.4.2. Verbs with multiple arguments 116
4.6. Discussion 119
4.6.1. Total years of exposure 122
4.6.2. Advantage of a homesign 123
4.6.3. Reanalysis or imperfect learning? 124

5. Study III: Comprehension of verbal inflection and classifiers 127
5.1. Introduction 127
5.2. Method 128
5.2.1. Subjects 128
5.2.2. Materials 128
5.2.3. Procedure 129
5.2.4. Coding and analyses 129
5.2.4.1. Accuracy 129
5.2.4.2. Iterative FALL 130
5.2.4.3. Uninflected FALL 130
5.2.4.4. Proportion of iterative selections 131
5.2.4.5. Iterative - Uniterative interchangeability 131
5.2.4.6. Object classifier FEATHERS 131
5.2.4.7. Handling classifier FEATHERS 132
5.2.4.8. Proportion of many-feathers selections 132
5.2.4.9. Object classifier - handling classifier interchangeability 133
5.3. Results 133
5.3.1. Accuracy 133
5.3.2. Iterative FALL 133
5.3.3. Uninflected FALL 134
5.3.4. Proportion of iterative selections 134
5.3.5. Iterative - Uniterative interchangeability 134
5.3.6. Object classifier FEATHERS 134
5.3.7. Handling classifier FEATHERS 135
5.3.8. Proportion of many-feathers selections 135
5.3.9. Object classifier - handling classifier interchangeability 135
5.4. Discussion 135

6. The Deverbal Anaphor Construction 139
6.1. Description 139
6.2. Examples 141

7. The order of the emergence of forms 145
7.1. Introduction 145
7.2. Method 146
7.3. Results 147
7.4. Discussion 148
7.5. Serial verb constructions in Nicaraguan signing 150
7.5.1 Description of the construction 151
7.6. Conclusion 153

8. Conclusion: A community creates a language 155
8.1. The emergence of a community 156
8.2. The emergence of a language 156
8.3. Evidence that the changes originate in the children 157
8.3.1. Age at Entry 157
8.3.2. Year of Entry 158
8.4. Nativization as language acquisition 158
8.5. The crucial community component 160
8.6. Phylogeny recapitulates ontogeny 161

References 163
Appendix A 171