Valter Ciocca’s research while affiliated with University of British Columbia and other places

The presence of noise is a salient cue to the perception of breathiness and aspiration in speech sounds. The detection of noise within harmonic series (maskers) composed of unresolved components was found to depend on the fundamental frequency (fo) and the overall level of the masker [Gockel, Moore, and Patterson (2002). J. Acoust. Soc. Am., 111 (6), 2759–2770]. In the present study, noise detection thresholds were measured as a function of the frequency range, the fo, and the overall level of harmonic maskers. Frequency range was specified in equivalent rectangular bandwidth (ERB) units (3–13, 13–23, 23–33, or 3–33 ERBs). The results were consistent with the idea that listeners rely on spectral cues when maskers comprise only resolved components (3–13 ERBs), and on temporal (dip listening) cues when maskers contain only unresolved components (23–33 ERBs). Noise detection thresholds were generally lower when masker level was high (70 dBA) than when it was low (50 dBA). Masker fo affected thresholds only when listeners relied on spectral cues for noise detection. With the wideband (3–33 ERBs) masker, listeners likely detected noise by focusing on the frequency band (23–33 ERBs) with the most advantageous noise-to-harmonic ratio.

Intelligibility of temporally degraded speech was investigated with locally time-reversed speech (LTR) and its interrupted version (ILTR). Control stimuli comprising interrupted speech (I) were also included. Speech stimuli consisted of 200 Japanese meaningful sentences. In interrupted stimuli, speech segments were alternated with either silent gaps or pink noise bursts. The noise bursts had a level of − 10, 0 or + 10 dB relative to the speech level. Segment duration varied from 20 to 160 ms for ILTR sentences, but was fixed at 160 ms for I sentences. At segment durations between 40 and 80 ms, severe reductions in intelligibility were observed for ILTR sentences, compared with LTR sentences. A substantial improvement in intelligibility (30–33%) was observed when 40-ms silent gaps in ILTR were replaced with 0- and + 10-dB noise. Noise with a level of − 10 dB had no effect on the intelligibility. These findings show that the combined effects of interruptions and temporal reversal of speech segments on intelligibility are greater than the sum of each individual effect. The results also support the idea that illusory continuity induced by high-level noise bursts improves the intelligibility of ILTR and I sentences.

Purpose To provide preliminary reference data for singleton consonant development in children with typical development (TD) versus protracted phonological development (PPD) for Manitoba Canadian French, a language with an uncommon stress pattern (“iambic” or “right-headed”). Following a nonlinear perspective, singleton consonants were examined both as segments and in terms of the structure of words. Higher match levels for consonants were expected in shorter versus longer words and in stressed versus unstressed syllables. A larger effect was expected in children with PPD than those with TD. Method Participants included 20 TD children and 12 with PPD aged 2 to 4 years from Manitoba, Canada. Single words were digitally recorded by trained speech-language pathologists, transcribed by native French speakers and analysed with Phon 3.0. Result Friedman and Wilcoxon Signed Rank tests revealed that children with PPD had significantly more mismatches than TD children, especially in contexts of unstressed syllables in multisyllabic words. The most common mismatch (“error”) patterns were consonant substitution, consonant deletion and syllable deletion. Conclusion Word length and stress were found to influence consonant development within French, similar to findings in languages with left-headed or trochaic stress. Clinically, the findings underscore the relevance of considering the child’s entire phonological system for identification of strengths and needs in assessment and intervention.

Previous research showed that aspiration noise difference limens in moderately breathy /a/ vowels decreased as the spectral slope of the glottal source spectrum became increasingly steep [Kreiman and Gerratt, J. Acoust. Soc. Am. 131(1), 492–500 (2012)]. The current study investigated whether discrimination of aspiration noise levels was affected by differences in spectral shape due to vowel quality (/æ/ and /i/) and speaker identity (three male speakers) when the slope of the glottal source spectrum was fixed. The results showed that discrimination performance was worse overall for /i/ than /æ/, but the result may have resulted from relatively poor performance for the /i/ vowel of one speaker. Acoustic analyses of the stimuli were performed to estimate the association between acoustic properties and the perceptual outcomes. The results showed that both the smoothed cepstral peak prominence and the harmonic energy level between 2 and 5 kHz may account for the observed differences in aspiration noise discrimination among speakers within each vowel, but not for differences between vowel categories. It is possible that the relationship between the aspiration noise discrimination and aforementioned acoustic properties may be modulated by the spectral distribution of energy across frequency.

Numerous studies have investigated the detection of pure tones and harmonic series in noise, but far fewer studied the perception of noise in harmonic series. One such study [Gockel, Moore and Patterson, J. Acoust. Soc. Am., 111(6), 2759–2770 (2002)] demonstrated that the masking thresholds of noise in harmonic series maskers were affected by the fundamental frequency (F0) and the overall level of the series, and by the relative phase of the harmonic components. The maskers used by Gockel et al. comprised unresolved harmonics (10th and higher harmonics below 5 kHz) for which F0 and frequency range covaried. The current study investigated noise detection for three non-overlapping spectral bands of equal auditory filter bandwidths (ERBs). Bands included either resolved harmonics (B1), unresolved harmonics (B3), or both resolved and unresolved harmonics (B2). Masker F0 and overall level were also varied. A Bayesian linear mixed-effects analysis showed that noise detection was better for higher F0s in B1 and B2, and that a higher presentation level resulted in a small improvement in noise detection in B2. Noise detection was better for higher presentation levels in B3. The findings will be discussed in relation to predictions of auditory processing models [Patterson, Allerhand, Giguère, J. Acoust. Soc. Am. 98(4), 1890–1894 (1995)].

This article is an overview of research activities in the School of Audiology and Speech Sciences at the University of British Columbia in Vancouver, BC, Canada. See full text at: http://canadianaudiologist.ca/issue/volume-5-issue-1-2018/school-of-audiology-speech-sciences-feature/

Research on the acoustic correlates of breathiness has been plagued by a lack of consistent findings across studies and low intra- and inter-rater agreement. Sources of variability can arise from different sources including: differences in stimulus types (recorded or synthesized); differences in speaker groups (for recorded stimuli) or in synthesis parameters (for synthesized stimuli); differences in experimental methodologies (task type, number of repetitions, listener backgrounds and experience). This review discussed these sources of variability, and described solutions that have the potential to address the variability and the inconsistencies often reported in the literature. A critical appraisal of the evidence about the relative importance of various acoustic measures resulted in the identification of measures of periodicity, noise content, and high-to-low frequency energy as the most likely acoustic correlates of breathiness.

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.