Mechanisms of Phonological Change

My dissertation examines the social and linguistic implications of an ongoing allophonic restructuring in Philadelphia English, focusing on the question ``How does the production of individual speakers cause community-wide phonological change?''. Using sociolinguistic interviews with over 100 Philadelphians (Chapter 2), I find that the allophonic change under consideration exhibits robust social stratification by school networks: special admissions public schools are the first to acquire the new allophonic system (``NAS''), while open admissions Catholic schools are a conservative stronghold of the traditional system (``PHL''). In Chapter 3, I provide a phonological analysis of the traditional PHL system. In Chapter 4, I closely examine the speech of 46 intermediate generation speakers, finding that speakers produce variation between both allophonic systems. I also employ experimental methods (Chapter 5) to demonstrate that the abstract allophonic rules governing /ae/ tensing are the target of social evaluation, with listeners producing systematic evaluations of PHL and NAS. Finally, to test whether the change from PHL to NAS was the inevitable result of phonological simplification, I developed a computational simulation built using a principle of language acquisition (Yang, 2016) to demonstrate that this change was not the result of children simplifying their input data, but rather was most likely the result of dialect contact with in-moving speakers of the new system (Chapter 6).

My research provides one of the first pieces of direct empirical support for a unified theory of language change in which structural changes in syntax and phonology are implemented through the same mechanism of grammar competition. Below you can also find a brief summary of and link to each individual chapter, along with my favorite plot from that chapter.

Read the whole dissertation here!

Chapter 1: Introduction


tl;dr: What even is phonological change?.

Chapter 2: Phonological change in Philadelphia /ae/


tl;dr: The traditional Philadelphia /ae/ split (PHL) is being replaced by an incoming Nasal /ae/ split (NAS). This change is stratified by school network.

Chapter 3: Allophonic analysis of traditional Philadelphia /ae/


tl;dr: PHL is allophonic. Also, phonology can handle a precise and limited number of lexical exceptions.

Chapter 4: Intraspeaker variation in /ae/


tl;dr: Intermediate speakers learn both allophonic systems, and produce variation between these systems as a whole.

Chapter 5: The social evaluation of abstract phonological structure


tl;dr: Listeners are attuned to a systemic social evaluation of both allophonic systems.

Chapter 6: The inevitability of phonological change


tl;dr: Even though NAS is simpler than PHL, it is not inevitable that NAS would come to replace PHL.

Chapter 7: Discusion and conclusions


tl;dr: Community-wide phonological change occurs through grammar competition!