The Prosodic Typology of the Phonological Word in the Yazdi Variety of Persian: An Acoustic Approach

Different varieties of a language can belong to different prosodic types. Standard Persian (SP) has been classified as a stress accent language based on three acoustic parameters: a) the acoustic correlates of prominent syllables, b) prominence in focal constituents, and c) stress hierarchies. This study hypothesized that Yazdi Persian, with perceptually different word-level prominence pattern, might belong to a different prosodic type. Previous studies disagree on the position of word-level stress and its acoustic correlates in Yazdi. Using the same parameters applied to SP, this study examined the prominence pattern and prosodic typology of Yazdi. An analysis of nonce words in post-focal contexts showed that, despite deaccentuation, the duration of initial and final vowels was significantly higher than the other vowels, forming a “hammock” or edge-prominence pattern. To probe further, focal constructions were analyzed. Results showed that the penultimate vowel—rather than the first or fourth vowel, consistently had higher F0 values. This challenges the principle of culminativity. We argue that the hammock pattern of edge vowels marks word boundary, while increased F0 on the penultimate syllable in focal contexts reflects post-lexical prominence. These findings suggest that the Yazdi variety of Persian belongs to a non-stress accent type.
 
Extended Abstract

Introduction

The Yazdi variety of Persian presents a particularly interesting case for prosodic typology, as it differs perceptually from Standard Persian (SP) in its stress and prominence patterns. Previous studies have characterized SP as a stress accent language, based on acoustic evidence (Sadeghi, 2018; Masoumi, 2021). Previous research on Yazdi reported conflicting findings: some studies identify initial stress, while others argue for penultimate stress placement. These inconsistencies raise broader questions about whether Yazdi belongs to the stress accent type or whether it exhibits characteristics of a non-stress accent system. The present study contributes to this debate by employing an acoustic approach to analyze word-level prominence in Yazdi.

Theoretical Framework

This study situates itself within the framework of word-level prosodic typology, which distinguishes between stress accent and non-stress accent language types (Hyman, 2006) which are different in their acoustic, phonological, and perceptual features (Masoumi, 2022). The three acoustic features are (i) the acoustic correlates of prominent syllables, (ii) the prominence pattern of focused constituents, and (iii) stress hierarchies. Within this framework, the present study analyzes Yazdi to determine whether its word-level prominence patterns show the characteristics of stress accent systems or deviate towards a non-stress accent type.

Methodology

Vowels that occur in focal position carry pitch accent, and by comparing different vowels of each word in this position, one can examine the prominence pattern of focal constituents. On the other hand, vowels in the post-focal position provide some information about parameters including acoustic correlates of prominent syllables, and stress hierarchies. More specifically, vowels in post-focal position lack post-lexical prominence due to deaccentuation; therefore, it is possible to determine the acoustic correlates of lexical stress—provided that the language in question belongs to the stress accent type.
The research adopts a quantitative and experimental design. Participants included nine female and eight male native speakers of Yazdi Persian, aged between 25 and 51. Stimuli consisted of two four-syllable nonce words ([sɑʃɑsɑʃɑ] and [saʃasaʃa]) designed to control for vowel quality and syllable structure, alongside two real words of varying syllable counts ([ʔɑ'luʧe] “plum” and [ʔadɛ'bijɑt] “literature”). Each stimulus was embedded within carrier sentences that elicited both focal and post-focal contexts. Recordings were made under controlled conditions and using the Django open-source web framework, which is written in Python. Prior to the experiment, participants were instructed to respond naturally in Yazdi Persian.
In the next phase, the recorded data were segmented and acoustically analyzed using Praat software (Boersma & Weenik, 2023). The acoustic analyses focused on vowel duration, intensity, and F0. Statistical analysis was conducted in RStudio, where ANOVA tests were implemented to identify significant differences across syllables, followed by pairwise comparisons for finer distinctions.

Results & Discussion

Data analysis reveals a consistent hammock pattern (Zonneveld, 1982) of vowel duration across both nonce and real words in the Yazdi variety. In post-focal contexts, initial and final vowels exhibited significantly longer durations than medial vowels, while intensity and F0 showed no significant differences. This edge-prominence pattern (Moskal, 2011) suggests that duration functions less as a stress correlate and more as a boundary marker, signaling word edges. The hammock pattern has also been documented in Armenian and Canadian French, where edge syllables are prominent.
In focal contexts, however, the penultimate syllable of Yazdi data consistently shows increased F0, even though edge syllables retain their greater duration.
The longer duration of word edge vowels in both focal and post-focal positions confirms its role as a boundary marker for phonological words, indicating that this edge-prominence is not related to word stress. Moreover, in focal positions, the higher F0 of the penultimate syllable contradicts the principle of culminativity expected in stress accent systems. According to this principle, in stress accent systems, syllables that are prominent at the lexical level are also expected to attract prominence post-lexically. 

Conclusions & Suggestions

This study demonstrates that Yazdi Persian diverges from SP by exhibiting properties of a non-stress accent system. Edge syllable lengthening serves as a boundary cue rather than a lexical stress marker, while prominence under focus consistently targets the penultimate syllable, reflecting post-lexical rather than lexical prominence. These findings challenge earlier claims of initial or penultimate lexical stress in Yazdi and instead position the variety as a non-stress accent system.
By situating Yazdi within the stress vs. non-stress accent debate, this research not only refines our understanding of Persian prosodic variation but also contributes to the larger cross-linguistic project of word-prosodic typology.
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