Prosodic Strengthening and Focus Type in Persian: an EMA Study

This paper reports results from the first articulometric study on prosodic strengthening in Persian. We concentrate on fine-grained differences in the marking of three focus types (broad, narrow, and corrective). Thus, we examine effects of prosodic strengthening between pitch-accented words with varying degrees of prominence, rather than comparing focused/accented to unfocused/unaccented words. The results indicate that even within this subtle range of prominence degrees, speakers adjust parameters of the labial and lingual subsystems when articulating /ɑ/. Bayesian regression provides strong evidence for differences across focus types, most consistent between broad and corrective focus, while narrow focus generally falls in between the two conditions (and tends toward corrective focus). Directly comparing corrective to broad focus, we find an increase in magnitudes of displacement and higher peak velocities in the vertical (high-low) and horizontal (front-back) movement dimensions of the tongue body, as well as the lip aperture. In addition, the vertical dimension of the tongue and the lip aperture show longer movement durations. Only the lip aperture has longer time-to-peak-velocity intervals. We interpret the findings through the lens of the gestural model of Articulatory Phonology by explaining movement differences as arising from changes in the dynamical parameters of the gestures.