Children’s Contribution to the Birth of Nicaraguan Sign Language

Ann Senghas

September, 1995

Abstract

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 become 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 Postion/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 76

4.4.3 Procedure 76

4.4.4 Coding 76

4.4.5 Analyses 77

4.5 Results 78

4.5.1 General measures of fluency 81

4.5.1.1 Morphemes per minute 81

4.5.1.2 Morphemes per sign 84

4.5.2 Verbal inflection 87

4.5.2.1 Position/location inflection 87

4.5.2.2 Person inflection 89

4.5.2.3 Shoulder shift 93

4.5.2.4 Aspectual inflection 95

4.5.2.5 Total inflections per verb 98

4.5.3 Verbal agreement 101

4.5.3.1 Position/location agreement 101

4.5.3.2 Person agreement 105

4.5.3.3 Total agreement per verb 108

4.5.4 Verb phrase complexity 111

4.5.4.1 Arguments per verb 111

4.5.4.2 Verbs with multiple arguments 114

4.6 Discussion 117

4.6.1 Total years of exposure 120

4.6.2 Advantage of a homesign 121

4.6.3 Reanalysis or imperfect learning? 122

5 Study III: Comprehension of verbal inflection and classifiers 125

5.1 Introduction 125

5.2 Method 126

5.2.1 Subjects 126

5.2.2 Materials 126

5.2.3 Procedure 127

5.2.4 Coding and analyses 127

5.2.4.1 Accuracy 127

5.2.4.2 Iterative FALL 128

5.2.4.3 Uninflected FALL 128

5.2.4.4 Proportion of iterative selections 129

5.2.4.5 Iterative – uniterative interchangeability 129

5.2.4.6 Object classifier FEATHERS 129

5.2.4.7 Handling classifier FEATHERS 130

5.2.4.8 Proportion of many-feathers selections 130

5.2.4.9 Object classifier – handling classifier

interchangeability 131

5.3 Results 131

5.3.1 Accuracy 131

5.3.2 Iterative FALL 131

5.3.3 Uninflected FALL 132

5.3.4 Proportion of iterative selections 132

5.3.5 Iterative – uniterative interchangeability 132

5.3.6 Object classifier FEATHERS 132

5.3.7 Handling classifier FEATHERS 133

5.3.8 Object classifier – handling classifier interchangeability 133

5.4 Discussion 133

6 The Deverbal Anaphor Construction 137

6.1 Description 137

6.2 Examples 139

7 The order of the emergence of forms 143

7.1 Introduction 143

7.2 Method 144

7.3 Results 145

7.4 Discussion 146

7.5 Serial verb constructions in Nicaraguan signing 148

7.5.1 Description of the construction 149

7.6 Conclusion 151

8 Conclusion: A community creates a language 153

8.1 The emergence of a community 154

8.2 The emergence of a language 154

8.3 Evidence that the changes originate in the children 155

8.3.1 Age at entry 155

8.3.2 Year of entry 156

8.4 Nativization as language acquisition 156

8.5 The crucial community component 158

8.6 Phylogeny recapitulates ontogeny 159