Vocal alignment to native and non-native speakers of English

Bibliometric Analysis and Review of Literature on the Relationship Between Voice Production and Bilingualism

BACKGROUND

The spoken language may influence the way we produce our voice. Therefore, speak more than one language could affect voice production. However, there is limited evidence on the relationship between voice production and bilingualism.

AIM

To characterize the relationship between bilingualism and voice production determined by means of voice acoustic parameters and voice perception.

METHODS

A review of literature was performed using four computerized databases. The keywords used were voice, bilingualism, and multilingualism. Relevant data were extracted from the publications on country and year of study, participants, sample size, characterization of voice production (acoustics, perceptual), and languages. A bibliometric analysis was performed for co-occurrence analysis. Quality assessment was conducted with the EPHPP tool.

RESULTS

A total of 10 publications met our inclusion criteria. Nine of the articles compared English productions with another language. Included studies reported changes in fundamental frequency between English and Spanish, Cantonese Chinese, Mandarin, Russian, Finnish, Arabic, Korean, Welsh, and Hebrew. The co-occurrence analysis shows that fundamental frequency is the most reported parameter, and English is the most compared language among studies including bilingual speakers.

CONCLUSION

Speaking a second language influences voice production determined by voice acoustic parameters, such as fundamental frequency. Therefore, language may be an important factor to take into consideration when planning assessment and intervention programs on the field of voice.

Phonetic entrainment in L2 human-robot interaction: an investigation of children with and without autism spectrum disorder

Phonetic entrainment is a phenomenon in which people adjust their phonetic features to approach those of their conversation partner. Individuals with Autism Spectrum Disorder (ASD) have been reported to show some deficits in entrainment during their interactions with human interlocutors, though deficits in terms of significant differences from typically developing (TD) controls were not always registered. One reason related to the inconsistencies of whether deficits are detected or not in autistic individuals is that the conversation partner's speech could hardly be controlled, and both the participants and the partners might be adjusting their phonetic features. The variabilities in the speech of conversation partners and various social traits exhibited might make the phonetic entrainment (if any) of the participants less detectable. In this study, we attempted to reduce the variability of the interlocutors by employing a social robot and having it do a goal-directed conversation task with children with and without ASD. Fourteen autistic children and 12 TD children participated the current study in their second language English. Results showed that autistic children showed comparable vowel formants and mean fundamental frequency (f0) entrainment as their TD peers, but they did not entrain their f0 range as the TD group did. These findings suggest that autistic children were capable of exhibiting phonetic entrainment behaviors similar to TD children in vowel formants and f0, particularly in a less complex situation where the speech features and social traits of the interlocutor were controlled. Furthermore, the utilization of a social robot may have increased the interest of these children in phonetic entrainment. On the other hand, entrainment of f0 range was more challenging for these autistic children even in a more controlled situation. This study demonstrates the viability and potential of using human-robot interactions as a novel method to evaluate abilities and deficits in phonetic entrainment in autistic children.

Speaking to a common tune: Between-speaker convergence in voice fundamental frequency in a joint speech production task

Recent research on speech communication has revealed a tendency for speakers to imitate at least some of the characteristics of their interlocutor’s speech sound shape. This phenomenon, referred to as phonetic convergence, entails a moment-to-moment adaptation of the speaker’s speech targets to the perceived interlocutor’s speech. It is thought to contribute to setting up a conversational common ground between speakers and to facilitate mutual understanding. However, it remains uncertain to what extent phonetic convergence occurs in voice fundamental frequency (F₀), in spite of the major role played by pitch, F₀’s perceptual correlate, as a conveyor of both linguistic information and communicative cues associated with the speaker’s social/individual identity and emotional state. In the present work, we investigated to what extent two speakers converge towards each other with respect to variations in F₀ in a scripted dialogue. Pairs of speakers jointly performed a speech production task, in which they were asked to alternately read aloud a written story divided into a sequence of short reading turns. We devised an experimental set-up that allowed us to manipulate the speakers’ F₀ in real time across turns. We found that speakers tended to imitate each other’s changes in F₀ across turns that were both limited in amplitude and spread over large temporal intervals. This shows that, at the perceptual level, speakers monitor slow-varying movements in their partner’s F₀ with high accuracy and, at the production level, that speakers exert a very fine-tuned control on their laryngeal vibrator in order to imitate these F₀ variations. Remarkably, F₀ convergence across turns was found to occur in spite of the large melodic variations typically associated with reading turns. Our study sheds new light on speakers’ perceptual tracking of F₀ in speech processing, and the impact of this perceptual tracking on speech production.