Investigating Arabic Guttural Coarticulation: Correlations of Larynx and Hyoid Bone Vertical Displacement with Vowel Formant Patterns

Guttural consonants in Arabic are characterized by articulation with an elevated larynx, a configuration that extends its influence to adjacent sounds. This coarticulatory effect produces measurable acoustic consequences, particularly in the formant structure of neighboring vowels. The present study investigates the relationship between larynx height, coarticulatory direction, and voicing in shaping the articulatory and acoustic modifications associated with guttural contexts. Using X-ray imaging, we examined the positional variations of the larynx during the production of the three short vowels /a, i, u/ adjacent to guttural consonants. Complementary acoustic analyses were conducted to evaluate the extent of formant shifts and changes in formant spacing induced by guttural spread. The findings indicate that guttural consonants exert a significant influence on vowel articulation and acoustics, with the magnitude of this effect strongly modulated by larynx height and voicing. By contrast, the direction of coarticulation (CV versus VC sequences) exhibited a comparatively weaker influence. Overall, the results provide clear evidence that laryngeal adjustments play a central role in the articulatory and acoustic properties of vowels in guttural environments. This study further demonstrates the utility of X-ray imaging for examining complex articulatory phenomena, offering valuable insights into the interplay between laryngeal movement and vowel acoustics in Arabic.