In this study, the relationship between the acoustic and articulatory kinematic domains of speech was examined among nine neurologically healthy female speakers using two derived relationships between tongue kinematics and F2 measurements: (1) second formant frequency (F2) extent to lingual displacement and (2) F2 slope to lingual speed. Additionally, the relationships between these paired parameters were examined within conversational, more clear, and less clear speaking modes. In general, the findings of the study support a strong correlation for both sets of paired parameters. In addition, the data showed significant changes in articulatory behaviors across speaking modes including the magnitude of tongue motion, but not in the speed-related measures.

This study examined the reliability and validity of speech-language pathologists’ (SLP) estimations of speech intelligibility in dysarthria, including a visual analog scale (VAS) method and a percent estimation method commonly used in clinical settings. Speech samples from 20 speakers with dysarthria of varying etiologies were used to collect orthographic transcriptions from naïve listeners n=70 and VAS ratings and percent estimations of intelligibility from SLPs n=21. Intra- and interrater reliability for the two SLP intelligibility measures were evaluated, and the relationship between these measures was assessed. Finally, linear regression was used to evaluate the relationship between the naïve listeners’ orthographic transcription scores and the two SLP intelligibility measures. The results indicated that the intrarater reliability for both SLP intelligibility measures was strong, and the interrater reliability between the SLP ratings was moderate to excellent. A moderate positive relationship between SLPs’ VAS ratings and percent estimations was also observed. Finally, both SLPs’ percent estimations and VAS ratings were predictive of naïve listeners’ orthographic transcription scores, with SLPs’ percent estimations being the strongest predictor. In conclusion, the average SLP percent estimations and VAS ratings are valid and reliable intelligibility measures. However, the validity and reliability of these measures vary between SLPs.

Purpose: This study aimed to examine the effects of wearing a face mask on speech acoustics and intelligibility, using an acoustic-phonetic analysis of speech. In addition, the effects of speakers' behavioral modification while wearing a mask were examined. Method: Fourteen female adults were asked to read a set of words and sentences under three conditions: (a) conversational, mask-off; (b) conversational, mask-on; and (c) clear, mask-on. Seventy listeners rated speech intelligibility using two methods: orthographic transcription and visual analog scale (VAS). Acoustic measures for vowels included duration, first (F1) and second (F2) formant frequency, and intensity ratio of F1/F2. For consonants, spectral moment coefficients and consonant–vowel (CV) boundary (intensity ratio between consonant and vowel) were measured. Results: Face masks had a negative impact on speech intelligibility as measured by both intelligibility ratings. However, speech intelligibility was recovered in the clear speech condition for VAS but not for transcription scores. Analysis of orthographic transcription showed that listeners tended to frequently confuse consonants (particularly fricatives, affricates, and stops), rather than vowels in the word-initial position. Acoustic data indicated a significant effect of condition on CV intensity ratio only. Conclusions: Our data demonstrate a negative effect of face masks on speech intelligibility, mainly affecting consonants. However, intelligibility can be enhanced by speaking clearly, likely driven by prosodic alterations.

Purpose: This study sought to determine if alternative vowel space area (VSA) measures (i.e., novel trajectory-based measures: vowel space hull area and vowel space density) predicted speech intelligibility to the same extent as two traditional vowel measures (i.e., token-based measures: VSA and corner dispersion) in speakers with dysarthria. Additionally, this study examined if the strength of the relationship between acoustic vowel measures and intelligibility differed based on how intelligibility was measured (i.e., orthographic transcriptions [OTs] and visual analog scale [VAS] ratings). Method: The Grandfather Passage was read aloud by 40 speakers with dysarthria of varying etiologies, including Parkinson's disease ( n = 10), amyotrophic lateral sclerosis ( n = 10), Huntington's disease ( n = 10), and cerebellar ataxia ( n = 10). Token- and trajectory-based acoustic vowel measures were calculated from the passage. Naïve listeners ( N = 140) were recruited via crowdsourcing to provide OTs and VAS intelligibility ratings. Hierarchical linear regression models were created to model OTs and VAS intelligibility ratings using the acoustic vowel measures as predictors. Results: Traditional VSA was the sole significant predictor of speech intelligibility for both the OTs ( R 2 = .259) and VAS ( R 2 = .236) models. In contrast, the trajectory-based measures were not significant predictors of intelligibility. Additionally, the OTs and VAS intelligibility ratings conveyed similar information. Conclusions: The findings suggest that traditional token-based vowel measures better predict intelligibility than trajectory-based measures. Additionally, the findings suggest that VAS methods are comparable to OT methods for estimating speech intelligibility for research purposes.

Purpose: To examine the predictive value of a selection of acoustic vowel measures for predicting intelligibility (i.e., measured using both orthographic transcriptions [OT] and visual analog scale [VAS] ratings) in speakers with dysarthria. The following questions were posed: (1) How well do trajectory-based and token-based vowel space measures predict intelligibility? And (2) does the relationship between vowel measures and intelligibility differ based on the type of intelligibility measurement (i.e., OT vs. VAS ratings)?Method: The Grandfather Passage was read aloud by forty speakers with dysarthria of varying etiologies, including Parkinson's disease (n = 10), amyotrophic lateral sclerosis (n = 10), Huntington's disease (n = 10), and cerebellar ataxia (n = 10). Token-based (i.e., acoustic vowel space area [VSA], corner dispersion) and trajectory-based (i.e., VSA hull area, and vowel space density [VSD]) acoustic vowel measures were calculated. Naïve listeners (N = 140) were recruited via crowdsourcing to provide OT and VAS intelligibility ratings. Hierarchical linear regression models were created to model OT and VAS ratings of intelligibility using the acoustic vowel measures as predictors.Results: Traditional VSA was the sole significant predictor of speech intelligibility for both the OT and VAS models. In contrast, the trajectory-based measures were not significant predictors of intelligibility. Additionally, the OT and VAS intelligibility ratings conveyed similar information.Conclusions: The findings suggest that traditional token-based vowel measures better predict intelligibility than trajectory-based measures. Additionally, the findings suggest that VAS methods are comparable to OT methods for estimating speech intelligibility for research purposes.