@article{GhaffarvandMokariSardhaei2020,
  author    = {Ghaffarvand Mokari, Payam and Sardhaei, Nasim Mahdinezhad},
  title     = {Predictive power of cepstral coefficients and spectral moments in the classification of Azerbaijani fricatives},
  series = {The journal of the Acoustical Society of America},
  volume    = {147},
  journal   = {The journal of the Acoustical Society of America},
  number    = {3},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0001-4966},
  doi       = {10.1121/10.0000830},
  pages     = {EL228 -- EL234},
  year      = {2020},
  abstract  = {This study compares the classification of Azerbaijani fricatives based on two sets of features: (a) spectral moments, spectral peak, amplitude, duration, and (b) cepstral coefficients employing Hidden Markov Models to divide each fricative into three regions such that the variances of the measures within each region are minimized. The cepstral coefficients were found to be more reliable predictors in the classification of all nine Azerbaijani fricatives and the cepstral measures yielded highly successful classification rates (91.21\% across both genders) in the identification of the full set of fricatives of Azerbaijani.},
  language  = {en}
}
@article{MokariGafosWilliams2021,
  author    = {Mokari, Payam Ghaffarvand and Gafos, Adamantios I. and Williams, Daniel},
  title     = {Perceptuomotor compatibility effects in vowels},
  series = {JASA Express Letters},
  volume    = {1},
  journal   = {JASA Express Letters},
  number    = {1},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {2691-1191},
  doi       = {10.1121/10.0003039},
  pages     = {8},
  year      = {2021},
  abstract  = {In a cue-distractor task, speakers' response times (RTs) were found to speed up when they perceived a distractor syllable whose vowel was identical to the vowel in the syllable they were preparing to utter. At a more fine-grained level, subphonemic congruency between response and distractor-defined by higher number of shared phonological features or higher acoustic proximity-was also found to be predictive of RT modulations. Furthermore, the findings indicate that perception of vowel stimuli embedded in syllables gives rise to robust and more consistent perceptuomotor compatibility effects (compared to isolated vowels) across different response-distractor vowel pairs.},
  language  = {en}
}
@article{GhaffarvandMokariGafosWilliams2020,
  author    = {Ghaffarvand-Mokari, Payam and Gafos, Adamantios I. and Williams, Daniel},
  title     = {Perceptuomotor compatibility effects in vowels},
  series = {Attention, perception, \& psychophysics},
  volume    = {82},
  journal   = {Attention, perception, \& psychophysics},
  number    = {5},
  publisher = {Springer},
  address   = {New York},
  issn      = {1943-3921},
  doi       = {10.3758/s13414-020-02014-1},
  pages     = {2751 -- 2764},
  year      = {2020},
  abstract  = {Perceptuomotor compatibility between phonemically identical spoken and perceived syllables has been found to speed up response times (RTs) in speech production tasks. However, research on compatibility effects between perceived and produced stimuli at the subphonemic level is limited. Using a cue-distractor task, we investigated the effects of phonemic and subphonemic congruency in pairs of vowels. On each trial, a visual cue prompted individuals to produce a response vowel, and after the visual cue appeared a distractor vowel was auditorily presented while speakers were planning to produce the response vowel. The results revealed effects on RTs due to phonemic congruency (same vs. different vowels) between the response and distractor vowels, which resemble effects previously seen for consonants. Beyond phonemic congruency, we assessed how RTs are modulated as a function of the degree of subphonemic similarity between the response and distractor vowels. Higher similarity between the response and distractor in terms of phonological distance-defined by number of mismatching phonological features-resulted in faster RTs. However, the exact patterns of RTs varied across response-distractor vowel pairs. We discuss how different assumptions about phonological feature representations may account for the different patterns observed in RTs across response-distractor pairs. Our findings on the effects of perceived stimuli on produced speech at a more detailed level of representation than phonemic identity necessitate a more direct and specific formulation of the perception-production link. Additionally, these results extend previously reported perceptuomotor interactions mainly involving consonants to vowels.},
  language  = {en}
}