Bryan Gick

Aero-tactile integration in speech perception

Visual information from a speaker’s face can enhance or interfere with accurate auditory perception. This integration of information across auditory and visual streams has been observed in functional imaging studies, and has typically been attributed to the frequency and robustness with which perceivers jointly encounter event-specific information from these two modalities. Adding the tactile modality has long been considered a crucial next step in understanding multisensory integration. However, previous studies have found an influence of tactile input on speech perception only under limited circumstances, either where perceivers were aware of the task or where they had received training to establish a cross-modal mapping. Here we show that perceivers integrate naturalistic tactile information during auditory speech perception without previous training. Drawing on the observation that some speech sounds produce tiny bursts of aspiration (such as English ‘p’), we applied slight, inaudible air puffs on participants’ skin at one of two locations: the right hand or the neck. Syllables heard simultaneously with cutaneous air puffs were more likely to be heard as aspirated (for example, causing participants to mishear ‘b’ as ‘p’). These results demonstrate that perceivers integrate event-relevant tactile information in auditory perception in much the same way as they do visual information.

Toward universals in the gestural organization of syllables: A cross-linguistic study of liquids

Abstract Asymmetries in the relative timing of gestures in English liquids and nasals have provided the basis for the beginnings of an articulatory definition of the syllable, and both perceptually and biomechanically based hypotheses have been proposed to explain these patterns. However, previous studies have not generally considered intergestural timing in languages other than English, making it impossible to distinguish between these hypotheses, or to substantiate claims of universality of these patterns. This paper presents an ultrasound study measuring intergestural timing of liquids in three syllable positions in six languages. Cross-linguistic generalizations in timing patterns among liquids are identified, and specific questions are tested. While much work remains to be done, results at this stage support the view that both perception (recoverability) and biomechanics (jaw movement cycles) are likely playing a role in determining intergestural timing patterns, with possible tendencies for perceptual recoverability to dominate in onsets and jaw movement cycles to dominate in codas.

A gesture-based account of intrusive consonants in English

A number of recent papers have demonstrated the advantages of using a phonological model incorporating the timing and magnitude of articulatory gestures to account for alternations involving segments such as the English nasals, liquids and glides (e.g. Krakow 1989, Browman & Goldstein 1992, 1995, Sproat & Fujimura 1993, Gick, in press). Some of these works (McMahon et al . 1994, McMahon & Foulkes 1995) have made specific reference to the well-known phenomenon of English intrusive r , shown in (1). formula here However, previous analyses have not linked the intrusive r explicitly to other similar processes, nor viewed all of these processes as the natural results of more general principles of phonological organisation. Thus, the intrusive r has remained, in the eyes of most linguists, an isolated quirk of English history, or, as one phonologist (McCarthy 1993: 191) has called it, ‘the phonologically unnatural phenomenon of r -epenthesis’. The present paper introduces into the discussion of intrusive r a recently documented related phenomenon known as intrusive l (Gick 1991, 1997, in preparation, Miller 1993). It is argued that these new facts, in conjunction with current advances in the understanding of articulatory factors in syllable structure, support a view in which the intrusive r and l are synchronically underlyingly present.

Speech habilitation of hard of hearing adolescents using electropalatography and ultrasound as evaluated by trained listeners

Four adolescents with moderate to severe sensorineural hearing losses and moderately unintelligible speech participated in a 14-week speech therapy study using two dynamic visual feedback technologies, electropalatography and ultrasound imaging. Electropalatography provides information about tongue-hard palate contact points. Ultrasound displays images of tongue shape and movement in two dimensions from the tip to the root. Treatment targets for all participants included a sibilant place contrast (/s/ versus / Z /), liquids /l/ and /r/, and the tense-lax vowel contrast with the high vowels. Trained listener evaluations of pre- and post-treatment transcripts are reported in this paper. Significant improvements in speech production were noted across students and targets. Treatment targets improved significantly more than non-treatment test targets overall. Students showed greatest gains on consonants that were absent or marginal in their speech pre-treatment. No particular advantage of one technology over the other was evident in this sample.

The Use of Ultrasound for Linguistic Phonetic Fieldwork

An increasingly wide variety of imaging and tracking technologies have been applied to measuring speech articulation in recent years. However, virtually all of these techniques have been restricted to laboratory or clinical settings. Portable ultrasound technology offers a way to conduct easy, non-invasive dynamic imaging of the whole tongue for less commonly studied languages, both in the field and in the laboratory.

Ultrasound in Speech Therapy with Adolescents and Adults.

The present paper comprises an overview of techniques using ultrasound in speech (re)habilitation. Ultrasound treatment techniques have been developed for English lingual stops, vowels, sibilants, and liquids. These techniques come from a series of small n studies with adolescents and adults with severe hearing impairment, residual speech impairment or accented speech at the Interdisciplinary Speech Research Laboratory at the University of British Columbia. Ultrasound allows excellent visualization of tongue shape features, which is especially useful for feedback during speech (re)habilitation. Further research is needed to evaluate the efficacy of ultrasound in speech (re)habilitation.

Language-Specific Articulatory Settings: Evidence from Inter-Utterance Rest Position

The possible existence of language-specific articulatory settings (underlying or default articulator positions) has long been discussed, but these have proven elusive to direct measurement. This paper presents two experiments using X-ray data of 5 English and 5 French subjects linking articulatory setting to speech rest position, which is measurable without segmental interference. Results of the first experiment show that speech rest position is significantly different across languages at 5 measurement locations in the vocal tract, and is similar to previously described language-specific articulatory settings. The second experiment shows that the accuracy of achievement of speech rest position is similar to that of a specified vowel target (/i/). These results have implications for the phonetics and phonology of neutral vowels, segmental nventories, and L2 acquisition.

MRI evidence for commonality in the post-oral articulations of English vowels and liquids

Abstract One advantage of using articulatory gestures in models of speech production is that a single gesture can function as a component in a number of different traditional segments (e.g., the tongue tip constrictions for /t/, /d/, /n/ and /l/). Few such claims, however, have been made with reference to more dorsal tongue gestures such as those in American /r/ and /l/. The present paper tests a proposed connection between the pharyngeal components of English liquids and vowels. Midsagittal MRIs of the vocal tracts of three speakers of American English were collected during the production of all vowels in each subjects inventory, plus /r/ and /l/. Midsagittal distances between the tongue and opposing surfaces were measured at intervals along the length of the vocal tract, and the vocal tract was divided into regions: lower pharyngeal, upper pharyngeal, uvular and oral. Vowel shapes were subtracted point by point from /r/ and /l/, allowing a single RMS difference to be calculated within each region of the vocal tract. Results support the prediction that, at least in some dialects, a single postoral gesture is shared between /l/ and /c:/, and between /r/ and schwa.

Techniques for field application of lingual ultrasound imaging.

Techniques are discussed for using ultrasound for lingual imaging in field‐related applications. The greatest challenges we have faced distinguishing the field setting from the laboratory setting are the lack of controlled head/transducer movement, and the related issue of tissue compression. Two experiments are reported. First, a pilot study identifies important factors in controlling head/transducer movement in field settings. Second, an Optotrak/ultrasound study reports the range of head movement in an optimal field‐like setting within and across varying phonetic contexts, as well as the effect of tongue tissue compression on tongue image data. Results suggest that with a simple arrangement involving a head rest or surface, a fixed transducer, and careful design and presentation of stimuli, reliable lingual ultrasound data can be collected in the field.

Spatial and Temporal Properties of Gestures in North American English /R/

Systematic syllable-based variation has been observed in the relative spatial and temporal properties of supralaryngeal gestures in a number of complex segments. Generally, more anterior gestures tend to appear at syllable peripheries while less anterior gestures occur closer to syllable peaks. Because previous studies compared only two gestures, it is not clear how to characterize the gestures, nor whether timing offsets are categorical or gradient. North American English /r/ is an unusually complex segment, having three supralaryngeal constrictions, but technological limitations have hindered simultaneous study of all three. A novel combination of M-mode ultrasound and optical tracking was used to measure gestural relations in productions of /r/ by nine speakers of Canadian English. Results show a front-to-back timing pattern in syllable-initial position: Lip then tongue blade (TB), then tongue root (TR). In syllable-final position TR and Lip are followed by TB. There was also a reduction in magnitude affecting Lip and TB gestures in syllable-final position and TR in syllable-initial position. These findings are not wholly consistent with any theory advanced thus far to explain syllable-based allophonic variation. It is proposed that the relative magnitude of gestures is a better predictor of timing than relative anteriority or an assigned phonological classification.