Atypical cortical hierarchy in Aß-positive older adults and its reflection in spontaneous speech.

Abnormal deposition of Aß amyloid is an early neuropathological marker of Alzheimer's disease (AD), arising long ahead of clinical symptoms. Non-invasive measures of associated early neurofunctional changes, together with easily accessible behavioral readouts of these changes, could be of great clinical benefit. We pursued this aim by investigating large-scale cortical gradients of functional connectivity with functional MRI, which capture the hierarchical integration of cortical functions, together with acoustic-prosodic features from spontaneous speech, in cognitively unimpaired older adults with and without Aß positivity (total N = 188). We predicted distortions of the cortical hierarchy associated with prosodic changes in the Aß + group. Results confirmed substantially altered cortical hierarchies and less variability in these in the Aß + group, together with an increase in quantitative prosodic measures, which correlated with gradient variability as well as digit span test scores. Overall, these findings confirm that long before the clinical stage and objective cognitive impairment, increased risk of cognitive decline as indexed by Aß accumulation is marked by neurofunctional changes in the cortical hierarchy, which are related to automatically extractable speech patterns and alterations in working memory functions.

Dynamic specification of vowels in Hijazi Arabic.

Research on various languages shows that dynamic approaches to vowel acoustics - in particular Vowel-Inherent Spectral Change (VISC) - can play a vital role in characterising and classifying monophthongal vowels compared with a static model. This study's aim was to investigate whether dynamic cues also allow for better description and classification of the Hijazi Arabic (HA) vowel system, a phonological system based on both temporal and spectral distinctions. Along with static and dynamic F1 and F2 patterns, we evaluated the extent to which vowel duration, F0, and F3 contribute to increased/decreased discriminability among vowels. Data were collected from 20 native HA speakers (10 females and 10 males) producing eight HA monophthongal vowels in a word list with varied consonantal contexts. Results showed that dynamic cues provide further insights regarding HA vowels that are not normally gleaned from static measures alone. Using discriminant analysis, the dynamic cues (particularly the seven-point model) had relatively higher classification rates, and vowel duration was found to play a significant role as an additional cue. Our results are in line with dynamic approaches and highlight the importance of looking beyond static cues and beyond the first two formants for further insights into the description and classification of vowel systems.

Automated Classification of Cognitive Decline and Probable Alzheimer's Dementia Across Multiple Speech and Language Domains.

BACKGROUND: Decline in language has emerged as a new potential biomarker for the early detection of Alzheimer's disease (AD). It remains unclear how sensitive language measures are across different tasks, language domains, and languages, and to what extent changes can be reliably detected in early stages such as subjective cognitive decline (SCD) and mild cognitive impairment (MCI). METHOD: Using a scene construction task for speech elicitation in a new Spanish/Catalan speaking cohort (N = 119), we automatically extracted features across seven domains, three acoustic (spectral, cepstral, and voice quality), one prosodic, and three from text (morpholexical, semantic, and syntactic). They were forwarded to a random forest classifier to evaluate the discriminability of participants with probable AD dementia, amnestic and nonamnestic MCI, SCD, and cognitively healthy controls. Repeated-measures analyses of variance and paired-samples Wilcoxon signed-ranks test were used to assess whether and how performance differs significantly across groups and linguistic domains. RESULTS: The performance scores of the machine learning classifier were generally satisfactorily high, with the highest scores over .9. Model performance was significantly different for linguistic domains (p < .001), and speech versus text (p = .043), with speech features outperforming textual features, and voice quality performing best. High diagnostic classification accuracies were seen even within both cognitively healthy (controls vs. SCD) and MCI (amnestic and nonamnestic) groups. CONCLUSION: Speech-based machine learning is powerful in detecting cognitive decline and probable AD dementia across a range of different feature domains, though important differences exist between these domains as well. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.23699733.

Static and dynamic cues in vowel production in Hijazi Arabic.

Static cues such as formant measurements obtained at the vowel midpoint are usually taken as the main correlate for vowel identification. However, dynamic cues such as vowel-inherent spectral change have been shown to yield better classification of vowels using discriminant analysis. The aim of this study is to evaluate the role of static versus dynamic cues in Hijazi Arabic (HA) vowel classification, in addition to vowel duration and F3, which are not usually looked at. Data from 12 male HA speakers producing eight HA vowels in /hVd/ syllables were obtained, and classification accuracy was evaluated using discriminant analysis. Dynamic cues, particularly the three-point model, had higher classification rates (average 95.5%) than the remaining models (static model: 93.5%; other dynamic models: between 65.75% and 94.25%). Vowel duration had a significant role in classification accuracy (average +8%). These results are in line with dynamic approaches to vowel classification and highlight the relative importance of cues such as vowel duration across languages, particularly where it is prominent in the phonology.

Native Language Influence on Brass Instrument Performance: An Application of Generalized Additive Mixed Models (GAMMs) to Midsagittal Ultrasound Images of the Tongue.

This paper presents the findings of an ultrasound study of 10 New Zealand English and 10 Tongan-speaking trombone players, to determine whether there is an influence of native language speech production on trombone performance. Trombone players' midsagittal tongue shapes were recorded while reading wordlists and during sustained note productions, and tongue surface contours traced. After normalizing to account for differences in vocal tract shape and ultrasound transducer orientation, we used generalized additive mixed models (GAMMs) to estimate average tongue surface shapes used by the players from the two language groups when producing notes at different pitches and intensities, and during the production of the monophthongs in their native languages. The average midsagittal tongue contours predicted by our models show a statistically robust difference at the back of the tongue distinguishing the two groups, where the New Zealand English players display an overall more retracted tongue position; however, tongue shape during playing does not directly map onto vowel tongue shapes as prescribed by the pedagogical literature. While the New Zealand English-speaking participants employed a playing tongue shape approximating schwa and the vowel used in the word 'lot,' the Tongan participants used a tongue shape loosely patterning with the back vowels /o/ and /u/. We argue that these findings represent evidence for native language influence on brass instrument performance; however, this influence seems to be secondary to more basic constraints of brass playing related to airflow requirements and acoustical considerations, with the vocal tract configurations observed across both groups satisfying these conditions in different ways. Our findings furthermore provide evidence for the functional independence of various sections of the tongue and indicate that speech production, itself an acquired motor skill, can influence another skilled behavior via motor memory of vocal tract gestures forming the basis of local optimization processes to arrive at a suitable tongue shape for sustained note production.

Nasalisation in the Production of Iraqi Arabic Pharyngeals.

AIM: This paper presents the auditory and acoustic investigations of pharyngeal consonants in Iraqi Arabic (IA). While the contested place and manner of articulation of these sounds have been the subject of investigation in many studies, the focus here is novel: we set out to investigate the extent to which pharyngeals in IA are accompanied by auditory nasalisation and how widespread the effect is across oral and nasal contexts. METHODS: Auditory and acoustic properties of nasalization, as produced by nine male speakers of IA, were investigated in target words with oral, nasal, and pharyngeal environments. RESULTS: When combined with oral consonants, pharyngeals exhibit little or no nasalisation; however, when pharyngeal are combined with nasals, they exhibit various degrees of nasalisation, sometimes beyond what is found for a nasal environment alone. This is especially so for voiced pharyngeals, which display more nasalisation than their voiceless counterparts. A principle component analysis combining all the acoustic correlates examined demonstrates a definite contribution of pharyngeals to the presence of nasalisation. CONCLUSION: The epilaryngeal constriction and variability in the articulation of pharyngeals are thought to be responsible for the nasalisation effect and may act as potential drivers for sound change in IA pharyngeals.

Acoustic cue weighting in the singleton vs geminate contrast in Lebanese Arabic: The case of fricative consonants.

This paper is the first reported investigation of the role of non-temporal acoustic cues in the singleton-geminate contrast in Lebanese Arabic, alongside the more frequently reported temporal cues. The aim is to explore the extent to which singleton and geminate consonants show qualitative differences in a language where phonological length is prominent and where moraic structure governs segment timing and syllable weight. Twenty speakers (ten male, ten female) were recorded producing trochaic disyllables with medial singleton and geminate fricatives preceded by phonologically short and long vowels. The following acoustic measures were applied on the medial fricative and surrounding vowels: absolute duration; intensity; fundamental frequency; spectral peak and shape, dynamic amplitude, and voicing patterns of medial fricatives; and vowel quality and voice quality correlates of surrounding vowels. Discriminant analysis and receiver operating characteristics (ROC) curves were used to assess each acoustic cue's contribution to the singleton-geminate contrast. Classification rates of 89% and ROC curves with an area under the curve rate of 96% confirmed the major role played by temporal cues, with non-temporal cues contributing to the contrast but to a much lesser extent. These results confirm that the underlying contrast for gemination in Arabic is temporal, but highlight [+tense] (fortis) as a secondary feature.

The contested fifth liquid in Malayalam: a window into the lateral-rhotic relationship in Dravidian languages.

Apart from Tamil, Malayalam is the only Dravidian language that still retains a fifth liquid in its inventory (denoted as /ʐ/), a sound that can be traced back to Proto-Dravidian. The phonetic and phonological status of this sound has been the subject of considerable debate, both in terms of its rhotic versus lateral status and its phonetic realisation. Studies to date have been impressionistic, so this is the first acoustic study of all five liquids in Malayalam. Production data from 8 male speakers reveal that while /ʐ/ is realised as a central post-alveolar approximant, its ambiguous phonotactic patterning and mixed acoustic profile are contributors to its mixed identity. An understanding of the complex patterning of this sound, which straddles the rhotic/lateral divide, requires an appreciation of the role of secondary acoustic resonance in distinguishing members of a crowded liquid system and in preventing a /ʐ/-/ɭ/ merger.