Phonetics, Phonology, and Morphology

Speech Production Patterns in Producing Linguistic Contrasts are Partly Determined by Individual Differences in Anatomy.

Keith Johnson

This study explored correlations between (a) measures of vocal tract anatomy and (b) measuresof articulatory/linguistic contrasts in vowels and coronal fricatives. The data for the study comefrom the Wisconsin X-Ray MicroBeam Database (Westbury, 1994). The anatomical measuresincluded vocal tract length, oral cavity length, palate size and shape, as well as measures ofmaximal tongue protrusion and jaw wagging amplitude. Measures of the articulatory vowelspace included the range of x and y location at vowel midpoints for...

Head correction of point tracking data

Keith Johnson
Ronald L. Sprouse

This is a short paper comparing two approaches to head correction for Electro-MagneticArticulography (EMA) data collected with the Northern Digital Instruments “Wave” system. Inboth of these approaches, it is necessary to translate and rotate the sensor locations to theocclusal coordinate system. We found that point tracking error is greater by as much as doublewith the built-in NDI head correction method, compared to a three-sensor head correctionalgorithm. However, we conclude that the data are comparable, and that the two-sensor NDImethod is acceptable for phonetic research. A Python...

Phonetic feature encoding in human superior temporal gyrus.

Nima Mesgarani
Connie Cheung
Keith Johnson
Edward F. Chang

During speech perception, linguistic elements such as consonants and vowels are extracted from a complex acoustic speech signal. The superior temporal gyrus (STG) participates in high-order auditory processing of speech, but how it encodes phonetic information is poorly understood. We used high-density direct cortical surface recordings in humans while they listened to natural, continuous speech to reveal the STG representation of the entire English phonetic inventory. At single electrodes, we found response selectivity to distinct phonetic features. Encoding of acoustic properties was...

Effects of native language on compensation for coarticulation

Shinae Kang
Keith Johnson
Gregory Finley

This paper investigates whether compensation for coarticulation in speech perception can be mediated by native language. Substantial work has studied compensation as a consequence of aspects of general auditory processing or as a consequence of a perceptual gestural recovery processes. The role of linguistic experience in compensation for coarticulation potentially cross-cuts this controversy and may shed light on the phonetic basis of compensation. In Experiment 1, French and English native listeners identified an initial sound from a set of fricative-vowel syllables on a continuum from [...

Encoding of Articulatory Kinematic Trajectories in Human Speech Sensorimotor Cortex

Josh Chartier
Gopala K. Anumanchipalli
Keith Johnson
Edward F. Chang

When speaking, we dynamically coordinate movements of our jaw, tongue, lips, and larynx. To investigate the neural mechanisms underlying articulation, we used direct cortical recordings from human sensorimotor cortex while participants spoke natural sentences that included sounds spanning the entire English phonetic inventory. We used deep neural networks to infer speakers’ articulator movements from produced speech acoustics. Individual electrodes encoded a diversity of articulatory kinematic trajectories (AKTs), each revealing coordinated articulator movements toward specific vocal tract...

Spectral and temporal measures of coarticulation in child speech

Margaret Cychosz
Jan R. Edwards
Benjamin Munson
Keith Johnson

Speech produced by children is characterized by a high fundamental frequency which complicates measurement of vocal tract resonances, and hence coarticulation. Here two whole-spectrum measures of coarticulation are validated, one temporal and one spectral, that are less sensitive to these challenges. Using these measures, consonant-vowel coarticulation is calculated in the speech of a large sample of 4-year-old children. The measurements replicate known lingual coarticulatory findings from the literature, demonstrating the utility of these acoustic measures of coarticulation in speakers of...

The Delta F method of vocal tract length normalization for vowels.

Keith Johnson

Given the acoustic consequences of physiological differences between talkers, there is a practical need for effective and theoretically motivated procedures of vowel normalization to facilitate comparison of speech produced by people who differ by dialect or language. In addition, there is a question whether listeners might utilize a normalization procedure during speech perception. This paper reports the results of two studies that explore these questions—with particular focus on vocal tract length normalization. Drawing on research in speech engineering, where accurate estimates of vocal...

Sensorimotor adaptation of speech depends on the direction of auditory feedback alteration.

Hardik Kothare
Inez Raharjo
Vikram Ramanarayanan
Kamalini Ranasinghe
Benjamin Parrell
Keith Johnson
John F. Houde
Srikantan S. Nagarajan
A hallmark feature of speech motor control is its ability to learn to anticipate and compensate for persistent feedback alterations, a process referred to as sensorimotor adaptation. Because this process involves adjusting articulation to counter the perceived effects of altering acoustic feedback, there are a number of factors that affect it, including the complex relationship between acoustics and articulation and non-uniformities of speech perception. As a consequence, sensorimotor adaptation is hypothesised to vary as a function of the direction of the applied auditory feedback alteration...