This article addresses the phonological variability in Persian trill production through an experimental approach. In a production experiment, the phonetic diversity in /r/ production was examined through spectral measurements of FFT spectra and spectrograms of the desired regions of the target signals. Results show that the trill and approximant variants are the most dominant /r/ allophones, while the distribution of other varieties largely depends on the prosodic context (utterance initial, medial, or final), as well as vocalic (vowel quality) and consonantal (voice) contexts.
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