A Comprehensive Socio-phonetic Study of the Plosive /p/ and Fricative /f/ Merger among Pashto Speakers in Khyber Pakhtunkhwa

Abstract

Introduction: The phonological systems of a first language (L1) can fundamentally constrain the acquisition of a second language (L2), particularly in speech sound perception and production. In Pashto-English bilinguals, the absence of the voiceless labiodental fricative /f/ in the L1 inventory theoretically predicts a merger with the voiceless bilabial plosive /p/, a phenomenon anecdotally observed but lacking robust empirical validation. Existing models of second language acquisition often inadequately integrate sociolinguistic factors, resulting in an incomplete understanding of how such phonological features are embedded and vary within a speech community.

Objective: This study critically investigates the /f/-/p/ merger among Pashto speakers in Khyber Pakhtunkhwa, Pakistan, by employing a mixed-methods sociophonetic approach. The research aims to determine the systematic nature of the merger in both production and perception and to evaluate whether its social distribution reveals a change in progress, thereby highlighting limitations in purely cognitive models of phonological acquisition.

Method: A stratified sample of 60 native Pashto speakers, balanced for age, gender, and education, participated in an explanatory sequential design. Baseline production data was collected via word-list and passage reading tasks and analyzed acoustically (Voice Onset Time, spectral moments). Perception was tested through identification and discrimination tasks. A multiple regression analysis predicted a composite 'Merger Index' from sociolinguistic variables, and post-experiment interviews provided qualitative data on metalinguistic awareness.

Findings: Quantitative analysis revealed a robust production merger, with a 74% substitution rate of /p/ for /f/, and significant perceptual confusion (identification accuracy = 59.5%). Regression analysis identified age (β = .61, p < .001) and education level (β = .28, p = .008) as significant predictors of the merger. Qualitative evidence further indicated limited metalinguistic awareness and emerging social stigma associated with the vernacular variant.

Conclusion: The findings demonstrate conclusively that the /f/-/p/ merger is a systematic feature of Pashto-English, driven by L1 transfer and modulated by social identity. The study concludes by proposing a more integrated theoretical framework for second language phonology, advocating for the incorporation of sociolinguistic principles to fully explain contact-induced phonological phenomena.