Acoustic insights into coarticulatory dynamics in aphasia: Evidence from a semitic language

This is the first comprehensive study to examine the feasibility of using acoustic measures to characterize coarticulatory dynamics in Arabic speakers with Broca's aphasia, addressing a significant gap in the literature and contributing to both universal and culturally specific understandings of coarticulatory timing in aphasia. Five Palestinian Arabic-speaking participants with Broca's aphasia and five control speakers completed a repetition task involving initial fricative-vowel syllables. Using PRAAT software, the analysis incorporates both static and dynamic acoustic parameters, including formant values (F2 and F3), transition slopes and variability, Voice Onset Time (VOT), and intensity measures. Statistical analysis identified significant differences between the speaker groups, with individuals with Broca's aphasia exhibiting elevated and more variable formant values, prolonged and variable VOT patterns, and reduced intensity levels. Density mapping demonstrated broader distributions and increased variability in F2 and F3 frequencies, indicating disruptions in coarticulatory timing. Decreased spectral centroids and rapid intensity decay rates further highlighted reduced consistency in acoustic patterns. Contrary to findings from studies in other languages, our results indicate a delay in coarticulation rather than a complete loss, accompanied by increased variability in segmental transitions. The findings also underscore how Arabic's unique phonological structures shape coarticulatory dynamics and advance our understanding of phonetic variability in linguistically underrepresented populations. The study also acknowledges its limitations and underlines the need for tailored interventions targeting timing dynamics, intensity patterns, and acoustic clarity to enhance therapy for individuals with Broca's aphasia.