Publications

Abstract

Spoken language comprehension requires abstraction of linguistic information from speech, but the interaction between auditory and linguistic processing of speech remains poorly understood. Here, we investigate the nature of this abstraction using neural responses recorded intracranially while participants listened to conversational English speech. Capitalizing on multiple, language-specific patterns where phonological and acoustic information diverge, we demonstrate the causal efficacy of the phoneme as a unit of analysis and dissociate the unique contributions of phonemic and spectrographic information to neural responses. Quantitive higher-order response models also reveal that unique contributions of phonological information are carried in the covariance structure of the stimulus-response relationship. This suggests that linguistic abstraction is shaped by neurobiological mechanisms that involve integration across multiple spectro-temporal features and prior phonological information. These results link speech acoustics to phonology and morphosyntax, substantiating predictions about abstractness in linguistic theory and providing evidence for the acoustic features that support that abstraction.

Abstract

Recent work has claimed that (non-tonal) phonological patterns are subregular (Heinz 2011a,b, 2018; Heinz and Idsardi 2013), occupying a delimited proper subregion of the regular functions—the weakly deterministic (WD) functions (Heinz and Lai 2013; Jardine 2016). Whether or not it is correct (McCollum et al. 2020a), this claim can only be properly assessed given a complete and accurate definition of WD functions. We propose such a definition in this article, patching unintended holes in Heinz and Lai’s (2013) original definition that we argue have led to the incorrect classification of some phonological patterns as WD. We start from the observation that WD patterns share a property that we call unbounded semiambience, modeled after the analogous observation by Jardine (2016) about non-deterministic (ND) patterns and their unbounded circumambience. Both ND and WD functions can be broken down into compositions of deterministic (subsequential) functions (Elgot and Mezei 1965; Heinz and Lai 2013) that read an input string from opposite directions; we show that WD functions are those for which these deterministic composands do not interact in a way that is familiar from the theoretical phonology literature. To underscore how this concept of interaction neatly separates the WD class of functions from the strictly more expressive ND class, we provide analyses of the vowel harmony patterns of two Eastern Nilotic languages, Maasai and Turkana, using bimachines, an automaton type that represents unbounded bidirectional dependencies explicitly. These analyses make clear that there is interaction between deterministic composands when (and only when) the output of a given input element of a string is simultaneously dependent on information from both the left and the right: ND functions are those that involve interaction, while WD functions are those that do not.

Abstract

The existence of language-specific abstract sound-structure units (such as the phoneme) is largely uncontroversial in phonology. However, whether the brain performs abstractions comparable to those assumed in phonology has been difficult to ascertain. Using intracranial electroencephalography (EEG) recorded during a passive listening task, this study investigates the representation of phonological units in the brain and the relationship between those units, auditory sensory input, and higher levels of language organization, namely morphology. Leveraging the phonological neutralization of coronal stops to tap in English, this study provides evidence of a dissociation between acoustic similarity and phonemic identity in the neural response to speech. Moreover, leveraging morphophonological alternations of the regular plural and past tense, this study further demonstrates early (<500ms) evidence of dissociation between phonological form and morphological exponence. Together these results highlight the central nature of language-specific knowledge in sublexical language processing and improve our understanding of the ways language-specific knowledge structures and organizes speech perception in the brain.

Abstract

To convey meaning, human language relies on hierarchically organized, long-
range relationships spanning words, phrases, sentences and discourse. As the
distances between elements (e.g. phonemes, characters, words) in human
language sequences increase, the strength of the long-range relationships
between those elements decays following a power law. This power-law
relationship has been attributed variously to long-range sequential organiz-
ation present in human language syntax, semantics and discourse structure.
However, non-linguistic behaviours in numerous phylogenetically distant
species, ranging from humpback whale song to fruit fly motility, also demon-
strate similar long-range statistical dependencies. Therefore, we hypothesized
that long-range statistical dependencies in human speech may occur indepen-
dently of linguistic structure. To test this hypothesis, we measured long-range
dependencies in several speech corpora from children (aged 6 months–
12 years). We find that adult-like power-law statistical dependencies are present
in human vocalizations at the earliest detectable ages, prior to the production of
complex linguistic structure. These linguistic structures cannot, therefore, be
the sole cause of long-range statistical dependencies in language