Geographic mobility, lexical processing dynamics, and perceptual adaptation

Ohio State University, The, Columbus OH

Investigators

Abstract

Americans are geographically mobile: the US Census Bureau reports that over the last decade, approximately 11% of Americans have moved each year, including nearly 2% of Americans who have moved each year to a different state. When people move to a new place, they are likely to encounter people who speak with a dialect that differs from their own. In addition, even non-mobile people who live in urban areas are likely to encounter people who have moved to the city from a place with a different dialect. As a result of this geographic mobility, Americans are exposed to substantial variation in regional dialects throughout the lifespan. Some recent research suggests that exposure to different dialects as a result of geographic mobility affects how speech is processed in real time. In particular, greater exposure to dialect variation appears to make people more flexible in their parsing of the speech signal, potentially leading to more successful communication with people who speak unfamiliar dialects. The goal of this project is to understand how this flexibility in processing arises. An investigation of the factors underlying processing flexibility due to geographic mobility will allow for a consideration of how processing dialect variation compares to processing other difficult kinds of speech (such as fast speech, foreign-accented speech, and speech in noise or with an auditory prosthesis such as a cochlear implant), which has substantial implications for understanding the constraints on human flexibility in speech processing. The project will examine whether the processing flexibility observed among mobile people is limited to the specific dialects to which a listener has been exposed or applies more generally to all unfamiliar dialects. It will also examine how the number of dialects that a person has exposure to and when that exposure occurs (for example, in childhood, adolescence, or adulthood) affects their processing flexibility for both familiar and unfamiliar dialects. Flexibility in speech processing will be examined in a series of speech perception experiments assessing the time course of word recognition and of adaptation to unfamiliar regional dialects. The specificity of the processing mechanism will be assessed by examining speech processing as a function of familiarity with particular regional dialects, such as Northern, Southern, and Mid-Atlantic American English. The effects of the amount and timing of dialect exposure will be assessed by recruiting a large sample of adult participants with a range of residential histories and travel experiences. All of the data collection for the project will be conducted in a language research laboratory that is located within a science museum in central Ohio. Study participants will be recruited from among the museum visitors, leading to direct public engagement with the research. Outreach materials related to the project will also be developed for the participants and other museum visitors to broaden the public impact of the work beyond the scholarly community. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.