Growing a Spatial Grammar: The Emergence of Verb Agreement in Nicaraguan Sign Language Language of Presentation: English The young sign language in Nicaragua has provided researchers with a unique opportunity: the chance to study a language from its birth. With the founding of a new school for special education in Managua approximately thirty years ago, Deaf Nicaraguans came together in greater numbers than ever before. Though teaching in this school was exclusively in written Spanish, students soon began to communicate manually, giving birth to a new language: Nicaraguan Sign Language (NSL). Each year children enter the school and learn the language naturally from their older peers, eventually becoming Deaf adults who use NSL for daily communication. As succeeding cohorts learn NSL, the language itself grows and changes, yielding the unique opportunity to view the language’s development by comparing signers of succeeding cohorts. One area in Nicaraguan Sign that has shown striking development is the emergence of verb agreement. Mature sign languages around the world use space to indicate agreement between verbs and their subjects and objects; however, little work examines how this type of agreement arises. We investigate the emergence of spatial verb agreement in Nicaraguan Sign Language across four groups: adult Nicaraguan homesigners (n=4, isolated individuals who have not learned NSL but communicate manually though systems of their own creation) and three cohorts of adult Nicaraguan signers (n=4 per cohort, average ages cohort 1: 39.5 years, cohort 2: 28.5 years, cohort 3: 20.25 years). All individuals viewed a series of short clips of transitive and intransitive events and then were asked to describe what they had seen. Responses were coded and analyzed for axis of verb articulation (sagittal vs. horizontal, after Padden, Meir, Aronoff, and Sandler, 2010) and agreement with nominals. We find that the emergence of spatial verb agreement is not monolithic and that its developmental trajectory is gradual and discontinuous. The seeds of spatial agreement are present even in adult homesigners, but even by the third cohort of adult signers, a full system of spatial verb agreement is still not in place. In fact, second cohort signers display higher levels of spatial verb agreement than do their younger third cohort peers (Figure 1). Although the third cohort signers institute sweeping changes into the language’s spatial grammar system, this change seems to come at a cost to the verb agreement system. The youngest signers are reorienting the language to function not only on a sagittal axis (straight out from the signer’s body), as is seen among older signers’ productions, but also on the horizontal axis (Figure 2). The signers do not, however, always set up their nominals along the same axis as their verbs. Time and continued study will reveal if younger cohorts of signers produce a language that spatially resembles the other sign languages of the world and is also rich in spatial verb agreement. By observing the continued development of verb agreement in Nicaraguan Sign we can see just how the processes of time and iterated transmission give rise to natural language structure. Words: 491 100% 90% 80% 70% 60% Subject & Object 50% Object 40% Subject 30% None 20% 10% 0% Homesigners Cohort 1 Cohort 2 Cohort 3 Figure 1. Spatial verb agreement by group of signers. Cohort 3 has a higher proportion of sentences with no spatial agreement or with only one semantic element marked than cohort 2 and, in this sense, uses less spatial agreement. 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Diagonal Axis Horizontal Axis Sagittal Axis Figure 2. Spatial layout axis use by group of signers. Cohort 3 makes greater use of the horizontal than the other groups. References Padden, C., Meir, I., Aronoff, M., Sandler, W. (2010) The grammar of space in two new sign languages. In D. Brentari (ed.) Sign Languages, 570-592. Cambridge, UK: Cambridge University Press.