This webinar convened researchers at the intersection of Artificial Intelligence and Neuroscience to investigate how large language models (LLMs) can serve as valuable “model organisms” for understanding human language processing. Presenters showcased evidence that brain recordings (fMRI, MEG, ECoG) acquired while participants read or listened to unconstrained speech can be predicted by representations extracted from state-of-the-art text- and speech-based LLMs. In particular, text-based LLMs tend to align better with higher-level language regions, capturing more semantic aspects, while speech-based LLMs excel at explaining early auditory cortical responses. However, purely low-level features can drive part of these alignments, complicating interpretations. New methods, including perturbation analyses, highlight which linguistic variables matter for each cortical area and time scale. Further, “brain tuning” of LLMs—fine-tuning on measured neural signals—can improve semantic representations and downstream language tasks. Despite open questions about interpretability and exact neural mechanisms, these results demonstrate that LLMs provide a promising framework for probing the computations underlying human language comprehension and production at multiple spatiotemporal scales.

Over the past 50 years, sociolinguistic studies on black Americans have expanded in both theoretical and technical scope, and newer research has moved beyond seeing speakers, especially black speakers, as a monolithic sociolinguistic community (Wolfram 2007, Blake 2014). Yet there remains a dearth of critical work on complex identities existing within black American communities as well as how these identities are reflected and perceived in linguistic practice. At the same time, linguists have begun to take greater interest in the ways in which public figures, such as politicians, may illuminate the wider social meaning of specific linguistic variables. In this talk, I will present results from analyses of multiple aspects of ethnolinguistic variation in the speech of Vice President Kamala Harris during the 2019-2020 Democratic Party Primary debates. Together, these results show how VP Harris expertly employs both enregistered and subtle linguistic variables, including aspects of African American Language morphosyntax, vowels, and intonational phonology in the construction and performance of a highly specific sociolinguistic identity that reflects her unique positions politically, socially, and racially. The results of this study expand our knowledge about how the complexities of speaker identity are reflected in sociolinguistic variation, as well as press on the boundaries of what we know about how speakers in the public sphere use variation to reflect both who they are and who we want them to be.