Colloquium: Molly Flaherty (University of Edinburgh)

Event Date: 

Monday, January 29, 2018 - 3:30pm

Event Location: 

  • Arts 1353

Speaker: Molly Flaherty (University of Edinburgh)

Topic: How Developing Minds Build a New Language: The Emergence of Nicaraguan Sign Language

Reception: All are invited to a reception following the talk

How Developing Minds Build a New Language:

The Emergence of Nicaraguan Sign Language


Molly Flaherty

University of Edinburgh


In this talk, I will give an overview of my research investigating the interaction between language input and the developing mind. I will closely examine a case of atypical first language learning: that of deaf children learning and creating a new language in Nicaragua. In this presentation, I will explore how the same forces at work in typical child language learning also build language structure when typical language input is not available. I use a range of methods and tools to explore the relative contributions of language input, language learning, and community interaction in building Nicaragua Sign Language (NSL). I will begin by discussing the growth of syntactic structure in homesign (manual communication systems created by isolated deaf individuals) and NSL by tracking the emergence of devices to mark argument structure. I find that the emergence of argument structure marking is neither instantaneous nor monolithic: some devices can be created by individual learners: homesigners and NSL signers of all generations employ these devices. Other markers show up only later with the addition of the language community and iterated transmission/learning of the language system. Next, I will turn to the emergence of structure at the morphological level and ask whether NSL signers have introduced overt marking of the morphological categories of noun and verb. I find that this distinction grows gradually: it appears in early Nicaraguan Sign Language and even in homesign, but increases in frequency as generations of children learn and pass down the language. Additionally, I will describe the gestural raw materials to Nicaraguan homesign and sign, and examine whether the gesture-rich communicative culture in Nicaragua may have been a particularly fertile environment in which to grow a new language. Finally, I investigate the cognitive consequences of not learning a mature language in childhood. I will present results indicating that in the domain of numerical cognition, individuals who do not learn number words, even if they are immersed in a world full of number, are unable to track exact quantity above five. In conclusion, I will show that the shape of language derives from human learning and use, and that one’s specific childhood language environment can have lifelong cognitive consequences.