The purpose of this study was to explore the speaker-discriminatory potential of vowel formant mean frequencies in comparisons of identical twin pairs and non-genetically related speakers. The influences of lexical stress and the vowels’ acoustic distances on the discriminatory patterns of formant frequencies were also assessed. Acoustic extraction and analysis of the first four speech formants F1-F4 were carried out using spontaneous speech materials. The recordings comprise telephone conversations between identical twin pairs while being directly recorded through high-quality microphones. The subjects were 20 male adult speakers of Brazilian Portuguese (BP), aged between 19 and 35. As for comparisons, stressed and unstressed oral vowels of BP were segmented and transcribed manually in the Praat software. F1-F4 formant estimates were automatically extracted from the middle points of each labeled vowel. Formant values were represented in both Hertz and Bark. Comparisons within identical twin pairs using the Bark scale were performed to verify whether the measured differences would be potentially significant when following a psychoacoustic criterion. The results revealed consistent patterns regarding the comparison of low-frequency and high-frequency formants in twin pairs and non-genetically related speakers, with high-frequency formants displaying a greater speaker-discriminatory power compared to low-frequency formants. Among all formants, F4 seemed to display the highest discriminatory potential within identical twin pairs, followed by F3. As for non-genetically related speakers, both F3 and F4 displayed a similar high discriminatory potential. Regarding vowel quality, the central vowel /a/ was found to be the most speaker-discriminatory segment, followed by front vowels. Moreover, stressed vowels displayed a higher inter-speaker discrimination than unstressed vowels in both groups; however, the combination of stressed and unstressed vowels was found even more explanatory in terms of the observed differences. Although identical twins displayed a higher phonetic similarity, they were not found phonetically identical.

Spontaneous Speech Segmentation: Functional and Prosodic Aspects With Applications for Automatic Segmentation / A segmentação da fala espontânea: aspectos prosódicos, funcionais e aplicações para a tecnologia

Objectives. To assess the speaker -discriminatory potential of a set of fundamental frequency estimates in intraidentical twin pair comparisons and cross -pair comparisons (i.e., among all speakers). Participants. A total of 20 Brazilian Portuguese speakers of the same dialect, namely 10 male identical twin pairs aged between 19 and 35, were recruited. Method. The participants were recorded directly through professional microphones while taking part in a spontaneous dialogue over mobile phones. Acoustic measurements were performed in connected speech samples, and in lengthened vowels, at least 160 ms long produced during spontaneous speech. Results. f 0 baseline, central tendency, and extreme values were found mostly discriminatory in intra-twin pair and cross -pair comparisons. These were also the estimates displaying the largest effect sizes. Overall, only three identical twins were found statistically different regarding their f 0 patterns in connected speech, but not for lengthened vowel -based f0 metrics. Estimates off 0 variation and modulation were found the least discriminatory across speakers, which may signal the control of speaking style and dialect on dynamic patterns off 0. Concerning system performance, the base value off 0 (f 0 baseline) was found the most reliable metric, displaying the lowest equal error rate (EER). Conclusions. The outcomes suggest that, although identical twins were very closely related regarding their f 0 patterns, some pairs could still be differentiated acoustically, only in connected speech. Such findings reinforce the relevance of analyzing long-term f 0 metrics for speaker comparison purposes, with particular consideration to f 0 baseline. Furthermore, f 0 differences across subjects were suggested as more expressive in connected speech than in lengthened vowels.

Estudos fonético-fonológicos sobre a língua de sinais americana (ASL) demonstraram que os itens lexicais dessa língua se constituem de unidades distintivas (parâmetros) e que estas, por sua vez, podem apresentar variação em sua manifestação concreta. Pouco se sabe sobre os parâmetros constitutivos dos sinais da língua brasileira de sinais (libras), tampouco sobre sua variação. Este trabalho representa um primeiro passo rumo a um entendimento de como se dá a variação na produção de sinais da libras a partir do estudo das produções, por 12 sinalizadores, de 60 sinais dessa língua. A análise dessas produções, eliciadas através de imagens combinadas com glosas em português, não apenas ratificou a ocorrência da variação inter-sujeito nos parâmetros configuração de mão, localização, movimento, orientação, número de mãos e marcações não-manuais, observada na sinalização espontânea, mas revelou também variação em outros aspectos articulatórios dos sinais, entre os quais está o contato entre os articuladores. Além disso, o estudo também evidenciou a ocorrência de variação intra-sujeito em todos os parâmetros analisados.