A unique property of the human mind is that it is capable of creating and acquiring languages. All groups of people have symbolic systems capable of expressing complex events and beliefs about the world, past experiences, and future aspirations. No other animal has a communication system with the scope and complexity of human languages, and no other animal can acquire such a system as readily as we do. What properties of the human mind give rise to language? How does the structure of language reflect the structure of the mind? What role do social interactions play in the emergence of language?

I explore these questions by studying homesign systems, gestural systems created by deaf individuals who do not acquire an external language, and Nicaraguan Sign Language, a new language only 50 years old. I also look at parallel questions using language creation paradigms with children and adults in the laboratory. More recently, I have started work looking at language comprehension using EEG in American Sign Language users.