Voice Research Articles

Voz masculina y voz femenina: su influencia en las evaluciones lingüísticas

The aim of this paper is to study how Granadian speakers (men and women) evaluate the female and male voices of the eight major varieties of Spanish suggested by Moreno Fernández (2009). Matched-guise technique-based PRECAVES XXI survey (Cestero Mancera and Paredes García, 2015, 2018) was completed by 54 men and 54 women from the province of Granada. Each respondent listened to 16 voice stimuli belonging to the eight geographic varieties previously mentioned. Half of the respondents listened to the female voice and the other half to the male voice. Analysis shows that in the data obtained from speakers of a stigmatised Granadian variety, a pattern can be observed that points to a higher evaluation of the female voice in those varieties that could be considered innovative, while the opposite is true in conservative varieties of Spanish, where the male voice is more highly valued. Surprisingly, this tendency is almost identical for informants of both sexes. We can conclude that in our study only the voice heard has a significant influence and that the linguistic prestige of the different modalities of Spanish is indeed related to the voice of the speaker, male or female, in accordance with Trudgill’s findings (1972, 1983).

Sa’idu Faru and His Subordinate Mu’azu in the Song Waƙar Mamman Sarkin Kudu: A Multilogue Implicature in a Dialogue

This is pragmatic research which focuses on the implicature in Sa’idu Faru’s song. The song is a musical composition performed by the human voice. The song may be performed by a solo singer, a lead singer supported by background singers (backing vocalists) a duet, a trio, or more voices singing in harmony. Apart from the melody that the voices carry in songs, meanings in the conversations in a song play a crucial role in identifying an implicature. Implicature are utterances and what is understood from them. As it is known in all his songs, Sa’idu Faru is the lead in his songs as in the song Waƙar Mamman Sarkin Kudu supported by vocalists, one of them is Mu’azu. However, in this song, as provided in some lines, Mu’azu is as important as the lead singer, which also, the vocalists are part that provides vocal harmony with the lead singer. If Mu’azu can be a vocalist like any other, then it is a dialogue between the lead and the vocalists but in this case where Mu’azu takes control in the conversation, then the song may be termed a duet. The conversational implicature in the song guided the researcher to understand that the song is a duet. The paper attempts to answer questions such as how are successive utterances related, who controls the discourse, how he does it and, how other participants take control. Gricean Maxims are adopted in the analyses of this paper.

FS2M: fuzzy smart IoT device pairing protocol via speak to microphone

Purpose This paper aims to provide a secure and efficient pairing protocol for two devices. Due to the large amount of data involving sensitive information transmitted in Internet of Things (IoT) devices, generating a secure shared key between smart devices for secure data sharing becomes essential. However, existing smart devices pairing schemes require longer pairing time and are difficult to resist attacks caused by context, as the secure channel is established based on restricted entropy from physical context. Design/methodology/approach This paper proposes a fuzzy smart IoT device pairing protocol via speak to microphone, FS2M. In FS2M, the device pairing is realized from the speaking audio of humans in the environment around the devices, which is easily implemented in the vast majority of Internet products. Specifically, to protect the privacy of secret keys and improve efficiency, this paper presents a single-round pairing protocol by adopting a recently published asymmetric fuzzy encapsulation mechanism (AFEM), which allows devices with similar environmental fingerprints to successfully negotiate the shared key. To instantiate AFEM, this paper presents a construction algorithm, the AFEM-ECC, based on elliptic curve cryptography. Findings This paper analyzes the security of the FS2M and its pairing efficiency with extensive experiments. The results show that the proposed protocol can achieve a secure device pairing between two IoT devices with high efficiency. Originality/value In FS2M, a novel cryptographic primitive (i.e., AFEM-ECC) are designed for IoT device pairing by using a new context-environment (i.e., human voice) . The experimental results show that FS2M has a good performance in both communication cost (i.e., 130 KB) and running time (i.e., 10 S).

Influence of flow rate and fiber tension on dynamical, mechanical and acoustical parameters in a synthetic larynx model with integrated fibers.

The human voice is generated by the oscillation of the vocal folds induced by exhalation airflow. Consequently, the characteristics of these oscillations and the primary sound signal are controlled by the longitudinal tension of the vocal folds, the flow rate, and their prephonatoric position. To facilitate independent control of these parameters, a synthetic larynx model was developed, as detailed in a previous publication. This study aims to statistically analyze the influence of airflow and fiber tension on phonation characteristics, such as periodicity and symmetry, glottis closure during vocal fold oscillations, as well as tissue elasticity and generated sound. A total of 76 experiments were conducted and statistically analyzed with a systematic variation of flow rate and longitudinal tension within the vocal folds.During these experiments, vocal fold motion, subglottal pressure, and emitted sound were meticulously measured and analyzed. Groupwise statistical testing identified the flow rate as the main influencing parameter on nearly all phonation characteristics. However, the fundamental frequency, stiffness parameters, and quality parameters of the primary sound signal are predominantly controlled by the longitudinal tension within the vocal folds. The results demonstrated a complex interplay between the flow rate and tension, resulting in different characteristics of the produced sound signal.

Infants' Preference for ID Speech in Face and Voice Extends to a Non‐Native Language

ABSTRACTInfants prefer infant‐directed (ID) speech. Concerning talking faces, previous research showed that 3‐ and 5‐month‐olds prefer faces that produce native ID than native adult‐directed (AD) speech, regardless of background speech being ID, AD or silent. Here, we explored whether infants also show a preference for non‐native ID speech. We presented 3‐ and 6‐month‐old infants with pairs of talking faces, one producing non‐native ID speech and the other non‐native AD speech, either in silence (Experiment 1) or accompanied by non‐native ID or AD background speech (Experiment 2). Results from Experiment 1 showed an overall preference for the silent ID talking faces across both age groups, suggesting a reliance on cross‐linguistic, potentially universal cues for this preference. However, Experiment 2 showed that preference for ID faces was disrupted at 3 months when auditory speech was present (ID or AD). At 6 months, infants maintained a preference for ID talking faces, but only when accompanied by ID speech. These findings show that auditory non‐native speech interferes with infants' processing of ID talking faces. They also suggest that by 6 months, infants start associating ID features from faces and voices irrespective of language familiarity, suggesting that infants' ID preference may be universal and amodal.

EVE - Your Personal AI Assistant

In today’s world, technology has become an essential part of our lives, with AI-powered voice assistants like Google Assistant, Alexa, and Siri seamlessly integrating into our daily routines. These assistants not only simplify tasks but also make technology more accessible. Eve, a personalized AI voice assistant, follows this trend by combining cutting-edge technology with Python to develop a smart, intuitive virtual assistant. Eve leverages the power of AI and machine learning (AI-ML), along with Python’s robust capabilities and Microsoft Azure’s Text-to-Speech platform. This provides users with natural-sounding male and female voices, enabling smooth and human-like interaction. Utilizing the dynamic Pyttsx library for text-to-speech synthesis, Eve creates a highly responsive and fine-tuned dialogue system that bridges the gap between the user and technology. Designed to act just like a human assistant, Eve can perform a wide variety of tasks through simple voice commands, such as opening applications, performing Wikipedia searches without the need for a browser, playing music, reading and summarizing PDFs, testing internet speed, and even handling tasks like Speak-to-Text, Google queries, Chrome tab management, image retrieval, live weather updates, word lookups, and event reminders. It also automates common desktop tasks like file search, open, close, and rename, all controlled through voice. This project demonstrates the creation of a personal desktop assistant using Python, aimed at improving convenience and automating tasks to assist users in their daily computer activities. Eve incorporates advanced features like voice recognition, natural language processing (NLP), and integration with external APIs to enrich its functionality and enhance the user experience. Designed with flexibility in mind, users can customize Eve’s behavior and functionality according to their specific needs while enjoying seamless integration with widely used tools and services. The user interface is crafted to be intuitive and easy to use, making Eve accessible to both beginners and experienced users alike. By combining personalization, automation, and ease of use, this project aspires to boost productivity and efficiency in everyday computer tasks.

Myoneurectomy for Adductor Spasmodic Dysphonia: Long-Term Outcomes, Complications, and Recurrence.

To evaluate the long-term results of endoscopic myoneurectomy (EMN) of the thyroarytenoid (TA) muscle for the treatment of adductor spasmodic dysphonia (AdSD), with an emphasis on vocal outcomes, adverse effects, and recurrence. A total of 48 patients underwent up to three EMNs of the TA muscle and were followed for at least 18 months to evaluate the efficacy, based on patient and examiner assessments, and safety of the procedure(s). Vocal outcomes were evaluated through the use of the 30-item Voice Handicap Index (VHI-30) questionnaire and subjective (patient-reported) assessment. In this group, 38 patients (79.2%) were considered successful. The median VHI-30 score at baseline was 97, decreasing to 26 after treatment, and the median subjective postprocedural improvement was 88.5%. The most common adverse effects were granulomas (in 18 cases), glottic insufficiency (in two), and dyspnea (in one). Although up to three procedures can be needed to achieve a high success rate, EMN of the TA muscle can provide excellent benefits in terms of vocal function with a low rate of complications. 4 Laryngoscope, 2024.

Talking Dogs: The Paradoxes Inherent in the Cultural Phenomenon of Soundboard Use by Dogs.

In recent years, dogs that appear to communicate with people by pressing buttons on soundboards that replay pre-recorded English words have become very popular on social media online. We explore how these dogs belong to a historical tradition that dates back at least to the Middle Ages and peaked in the early twentieth century. Through analyses of short videos, books, and training manuals, we identify several paradoxes inherent in this phenomenon. These include how the dogs appear to provide unmediated access to their thoughts, and yet, their button presses are typically incoherent and require interpretation. They also require months of training to "spontaneously" express themselves. There is also an anthropomorphism and -centrism in claiming that a human skill-language-is required for a dog to express mental states that it already possesses. This approach to communicating with dogs quiets canine forms of expression such as barking, whining, bodily postures, and odors and replaces them with endearing but infantile human voices. We suggest that, while this endeavor may be well intentioned and often playful, it runs the risk of skewing people's perception of dogs towards fur-clad infants rather than adult members of a different species and of making people less attentive to canine nonverbal communication.

Federated Learning Using Multi-Modal Sensors with Heterogeneous Privacy Sensitivity Levels

Data from multi-modal sensors, such as Red-Green-Blue (RGB) cameras, thermal cameras, microphones, and mmWave radars, have gradually been adopted in various classification problems for better accuracy. Some sensors, like RGB cameras and microphones, however, capture privacy-invasive data, which are less likely to be used in centralized learning. Although the Federated Learning (FL) paradigm frees clients from sharing their sensor data, doing so results in reduced classification accuracy and increased training time. In this article, we introduce a novel Heterogeneous Privacy Federated Learning (HPFL) paradigm to better capitalize on the less privacy-invasive sensor data, such as thermal images and mmWave point clouds, by uploading them to the server for closing the performance gap between FL and centralized learning. HPFL not only allows clients to keep the more privacy-invasive sensor data private, such as RGB images and human voices, but also gives each client total freedom to define the levels of their privacy concern on individual sensor modalities. For example, more sensitive users may prefer to keep their thermal images private, while others do not mind sharing these images. We carry out extensive experiments to evaluate the HPFL paradigm using two representative classification problems: semantic segmentation and emotion recognition. Several key findings demonstrate the merits of HPFL: (i) compared to FedAvg, it improves foreground accuracy by 18.20% in semantic segmentation and boosts the F1-score by 4.20% in emotion recognition, (ii) with heterogeneous privacy concern levels, it achieves an even larger F1-score improvement of 6.17–16.05% in emotion recognition, and (iii) it also outperforms the state-of-the-art FL approaches by 12.04–17.70% in foreground accuracy and 2.54–4.10% in F1-score.

Time for Care: Male and Female Voices Based on Their Caregiving Experiences.

Background/Objectives: To understand the lived experiences of the informal caregivers of people with chronic noncommunicable diseases and their interpretations of the significance of that care. The perspectives of men and women interacting with people in a situation of chronicity are examined. Methods: This qualitative, phenomenological, hermeneutic study was based on Van Manen's comprehensive and interpretative vision. Criterion-oriented non-probability random sampling was used. In-depth interviews were used to collect the information. Twenty informal caregivers participated in the study. Results: The following five themes emerged: transformation of the caregiver's world; uncertainty of care; tireless guardianship and unwavering devotion; isolation and emotional exhaustion; and imbalance between caring for others and the self. Conclusions: The experience of informal caregivers reveals that both men and women face significant challenges, albeit from gender-differentiated perspectives and experiences. Men and women elaborate different meanings of caregiving, reflecting their gender roles and expectations. Therefore, an inclusive and equitable approach that recognizes and addresses these gender differences is essential in order to improve the support and quality of life for all informal caregivers, respecting and valuing their unique voices and experiences. An inclusive and equitable approach that recognizes gender intersections is required to improve support and the quality of life for informal caregivers.

Identifying and Estimating Frailty Phenotypes by Vocal Biomarkers: Cross-Sectional Study.

Researchers have developed a variety of indices to assess frailty. Recent research indicates that the human voice reflects frailty status. Frailty phenotypes are seldom discussed in the literature on the aging voice. This study aims to examine potential phenotypes of frail older adults and determine their correlation with vocal biomarkers. Participants aged ≥60 years who visited the geriatric outpatient clinic of a teaching hospital in central Taiwan between 2020 and 2021 were recruited. We identified 4 frailty phenotypes: energy-based frailty, sarcopenia-based frailty, hybrid-based frailty-energy, and hybrid-based frailty-sarcopenia. Participants were asked to pronounce a sustained vowel "/a/" for approximately 1 second. The speech signals were digitized and analyzed. Four voice parameters-the average number of zero crossings (A1), variations in local peaks and valleys (A2), variations in first and second formant frequencies (A3), and spectral energy ratio (A4)-were used for analyzing changes in voice. Logistic regression was used to elucidate the prediction model. Among 277 older adults, an increase in A1 values was associated with a lower likelihood of energy-based frailty (odds ratio [OR] 0.81, 95% CI 0.68-0.96), whereas an increase in A2 values resulted in a higher likelihood of sarcopenia-based frailty (OR 1.34, 95% CI 1.18-1.52). Respondents with larger A3 and A4 values had a higher likelihood of hybrid-based frailty-sarcopenia (OR 1.03, 95% CI 1.002-1.06) and hybrid-based frailty-energy (OR 1.43, 95% CI 1.02-2.01), respectively. Vocal biomarkers might be potentially useful in estimating frailty phenotypes. Clinicians can use 2 crucial acoustic parameters, namely A1 and A2, to diagnose a frailty phenotype that is associated with insufficient energy or reduced muscle function. The assessment of A3 and A4 involves a complex frailty phenotype.

Anonymization of Voices in Spaces for Civic Dialogue: Measuring Impact on Empathy, Trust, and Feeling Heard

Anonymity is a powerful component of many participatory media platforms that can afford people greater freedom of expression and protection from external coercion and interference. However, it can be difficult to effectively implement on platforms that leverage spoken language due to distinct biomarkers present in the human voice. In this work, we explore the use of voice anonymization methods within the context of a technology-enhanced civic dialogue network based in the United States, whose purpose is to increase feelings of agency and being heard within civic processes. Specifically, we investigate the use of two different speech transformation and synthesis methods for anonymization: voice conversion (VC) and text-to-speech (TTS). Through a series of two studies, we examine the impact that each method has on 1) the empathy and trust that listeners feel towards a person sharing a personal story, and 2) a speaker's own perception of being heard, finding that voice conversion is an especially suitable method for our purposes. Our findings open up interesting potential research directions related to anonymous spoken discourse, as well as additional ways of engaging with voice-based civic technologies.

Morphological Evidence for a Unique Neuromuscular Functional Unit of the Human Vocalis Muscle.

Human vocalization is a complex process that is still only partially understood. Previous studies have suggested the possibility of a localized neuromuscular network of the larynx. Here we investigate this structure in human dissection specimens using multiple immunofluorescence and transmission electron microscopy (TEM). In the area of the pars interna of the thyroarytenoid muscle, muscle fibers are present that are clearly differentiated from skeletal or cardiac muscle cells and show an intermediate ultrastructure. In addition, intramuscular neurons are present that are detectable by both electron and fluorescence microscopy and may have a sensory function in a local neuronal network. Also, several types of sensory and motor synapses are detectable and distributed throughout the pars interna of the thyroarytenoid muscle, with multisynaptic muscle fibers being a common feature. These findings suggest the existence of a previously unrecognized type of muscle fiber coupled to an intramuscular neuronal network, the presence of which could explain functional peculiarities at the laryngeal level.

ESTIMATION OF FORMANT INFORMATION USING AUTOCORRELATION FUNCTION OF VOICE SIGNAL

Context. The current scientific problem of extracting biometric characteristics of a user of a voice authentication system, which can significantly increase its reliability, is considered. There has been performed estimation of formant information from the voice signal, which is a part of the user template in the voice authentication system and is widely used in the processing of speech signals in other applications, including in the presence of interfering noise components. The work is distinguished by the investigation of a polyharmonic signal. Objective. The purpose of the work is to develop procedures for generating formant information based on the results of calculating the autocorrelation function of the analyzed fragment of the voice signal and their subsequent spectral analysis. Method. The procedures for generating formant information in the process of digital processing of voice signal are proposed. Initially, the autocorrelation function of the analyzed fragment of the voice signal is calculated. Based on the results of the autocorrelation function estimation, the amplitude-frequency spectrum is calculated, from which the formant information is extracted, for example, by means of threshold processing. When the signal-to-noise ratio of the analyzed voice signal fragment is low, it is advisable to iteratively calculate the autocorrelation function. The latter allows increasing the signal-to-noise ratio and the efficiency of formant information extraction. However, each subsequent iteration of the autocorrelation function calculation is associated with an increase in the required computational resource. The latter is conditioned by the doubling of the amount of processed data at each iteration. Results. The developed procedures for generating formant information were investigated both in the processing of model and experimental voice signals. The model signals had a low signal-to-noise ratio. The proposed procedures allow to determine more precisely the width of the spectrum of extracted formant frequencies, significantly increase the number of extracted formants, including cases at low signal-to-noise ratio. Conclusions. The conducted model experiments have confirmed the performance and reliability of the proposed procedures for extracting formant information both in the processing of model and experimental voice signals. The results of the research allow to recommend their use in practice for solving problems of voice authentication, speaker differentiation, speech and gender recognition, intelligence, counterintelligence, forensics and forensic examination, medicine (diseases of the speech tract and hearing). Prospects for further research may include the creation of procedures for evaluating formant information based on phase data of the processed voice signal.

“Cats in congress or penguins in parliament”? Towards the just representation of more-than-humans in Antarctic environmental governance

ABSTRACT Representation is a core component of Rights of Nature (RoN). While giving a human voice to more-than-humans might be seen as anthropocentric, RoN is one of the best tools available in current legal frameworks and institutions to safeguard the interests of more-than-humans. However, challenges arise when looking at the Antarctic. In particular, the absence of a permanent population, a State, and an Indigenous people makes the designation of an Antarctic representative a delicate matter. More-than-humans are the only permanent residents of the Antarctic while being paradoxically excluded from Antarctic decision-making processes and institutions. This article explores the issue of ‘just representation’ of more-than-humans within the Antarctic Treaty System, based on theories of multispecies justice focusing on recognition and participation. It develops the political, legal, and theoretical frameworks for a just environmental governance in the Antarctic, looking at RoN to support some aspects of the ‘just representation’ of more-than-humans in the Antarctic.

Release from same-talker speech-in-speech masking: Effects of masker intelligibility and other contributing factorsa).

Human speech perception declines in the presence of masking speech, particularly when the masker is intelligible and acoustically similar to the target. A prior investigation demonstrated a substantial reduction in masking when the intelligibility of competing speech was reduced by corrupting voiced segments with noise [Huo, Sun, Fogerty, and Tang (2023), "Quantifying informational masking due to masker intelligibility in same-talker speech-in-speech perception," in Interspeech 2023, pp. 1783-1787]. As this processing also reduced the prominence of voiced segments, it was unclear whether the unmasking was due to reduced linguistic content, acoustic similarity, or both. The current study compared the masking of original competing speech (high intelligibility) to competing speech with time reversal of voiced segments (VS-reversed, low intelligibility) at various target-to-masker ratios. Modeling results demonstrated similar energetic masking between the two maskers. However, intelligibility of the target speech was considerably better with the VS-reversed masker compared to the original masker, likely due to the reduced linguistic content. Further corrupting the masker's voiced segments resulted in additional release from masking. Acoustic analyses showed that the portion of target voiced segments overlapping with masker voiced segments and the similarity between target and masker overlapped voiced segments impacted listeners' speech recognition. Evidence also suggested modulation masking in the spectro-temporal domain interferes with listeners' ability to glimpse the target.

Socialising the Frequency Code: Effects of gender and age on iconic associations of pitcha).

Burgeoning research has shown the pervasiveness of sound symbolism, a type of iconicity, in language. However, little work looks at how individual experiences and beliefs affect sound symbolic associations. We investigate pitch associations under the Frequency Code, which links high vs low pitch to small vs large body size and female vs male gender (via sexual dimorphism), long claimed to underlie "universal" meanings like submissiveness vs dominance. While such associations appear widespread, the Frequency Code assumes ideological links, e.g., between dominance and masculinity, which differ between individuals and cultures. In Implicit Association Task experiments with English-speaking listeners, we show high pitch is implicitly associated with small size and female gender, and low with large and male, following the Frequency Code. Crucially, though, the strength of these associations varies by social factors. Associations are stronger for male voices and listeners, particularly older men, as ideologies related to the Frequency Code (linking large size, strength, and dominance) tend to be stronger for men. The association of pitch with gender is stronger than with body size, reflecting stronger gender-based stereotypes. This work shows that social experience shapes and reinforces iconic associations, with important implications for how iconic meanings develop and are processed.

Temporal coherence shapes cortical responses to speech mixtures in a ferret cocktail party

Perceptual segregation of complex sounds such as speech and music simultaneously emanating from multiple sources is a remarkable ability that is common in humans and other animals alike. Unlike animal physiological experiments with simplified sounds or human investigations with spatially broad imaging techniques, this study combines insights from animal single-unit recordings with segregation of speech-like sound mixtures. Ferrets are trained to attend to a female voice and detect a target word, both in presence and absence of a concurrent equally salient male voice. Recordings are made in primary and secondary auditory cortical fields, and in frontal cortex. During task performance, representation of the female words becomes enhanced relative to the male in all, but especially in higher cortical regions. Analysis of the temporal and spectral response characteristics during task performance reveals how speech segregation gradually emerges in the auditory cortex. A computational model evaluated on the same voice mixtures replicates and extends these results to different attentional targets (attention to female or male voices). These findings underscore the role of the principle of temporal coherence whereby attention to a target voice binds together all neural responses coherently modulated with the target, thus ultimately forming and extracting a common auditory stream.

Symbolic Bureaucratic Representation and Client Cooperation: Experimental Insights From Four Daily Public Service Scenarios in China

ABSTRACTRepresentative bureaucracy studies have explored the potential impact of symbolic representation on clients' attitudes and behaviors, even in the absence of direct action by bureaucrats. Through four original conjoint experiments conducted with a nationally representative sample of 1600 participants in China, we analyze the symbolic representation effects of five most commonly observable identity signals, including gender, age, accent, party affiliation, and human voice (versus AI chatbot), across two types of bureaucrat‐initiated contacts and two types of client‐initiated contacts. Our findings contribute to the existing literature by demonstrating that identity congruence has heterogeneous symbolic representation effects; clients' expectations about active representation serve as a significant mediating factor influencing their willingness to cooperate with bureaucrats.

Value and appraisal: human resource management practices and voice behaviors

PurposeEmployee voice is considered an important driver of organizational success. Management practices in the form of high-performance work practices (HPWPs) are expected to influence promotive and prohibitive voices. In addition, employee appraisal of HPWPs as a challenge or hindrance stressor is supposed to mediate the relationships. Finally, the self-direction value moderates the indirect effects of HPWPs on voice behaviors through employee appraisal.Design/methodology/approachA quantitative research approach was adopted with data collected from 315 subordinate supervisor dyads from 12 business organizations in Vietnam. This research uses partial least square structural equation modeling (PLS-SEM) to test the hypotheses.FindingsResults indicate that HPWPs are significantly associated with both types of employee voice behaviors. Challenge appraisal partially mediates the impact of HPWPs on promotive voice, while hindrance appraisal acts as a partial mediation in the HPWPs-prohibitive voice linkage. Self-direction value moderates the link between HPWPs and prohibitive voice.Research limitations/implicationsResults show that HPWPs may have both productive and harmful effects on employees. Depending on how the employees appraise HPWPs, they develop different coping strategies by raising their voices. HPWP-implementing organizations should pay attention to the employees’ values in this process.Originality/valueThis study investigates the relationship between HPWPs and employee voice based on the transactional theory of stress and coping. The mediating role of employee appraisal represents a new contribution. Finally, the role of self-direction value in the voice literature has not been widely evaluated in previous research.