The pharyngeal cavity plays a crucial role in the production of Arabic emphatics and gutturals. These sounds are represented differently in phonological classification systems. Some phonological representations classify emphatics and gutturals according to place of articulation while others classify them according to the active articulator. These different classifications of Arabic emphatics and gutturals in feature geometry are due to insufficient phonetic knowledge about these consonants. As a consequence of an inadequate knowledge about the articulatory and acoustic characteristics of emphatics and gutturals, their representation in some classification systems does not adequately reflect certain phonological phenomena relating to them. Specifically, there are a number of phonological rules and constraints which present challenges to the current phonological representations of emphatics and gutturals although emphatics and gutturals share the same region of articulation. Furthermore, these phonological phenomena provide evidence which supports the classification of gutturals as a separate natural class in feature geometry. Therefore, it is proposed that a clear distinction should be drawn in the phonological representation of these sounds.
Although the articulatory gestures and acoustic properties of gutturals have been considered a basis for classifying gutturals as a natural class in feature geometry, there are still discrepancies between the articulatory gestures of gutturals, and their acoustic properties, which need to be resolved. It is proposed that gutturals are characterized by high F1 values. This is true of both pharyngeals and uvulars because they have a clear constriction in the pharyngeal cavity; however, glottals do not have a notable constriction in this region. On the other hand, shortening of the vocal tract by raised larynx could provide an alternative explanation for raised F1 during the production of glottals. Laryngeal movements involved in the production of gutturals are therefore investigated in this study to see if this gesture represents an alternative cause of F1 raising by gutturals.
It is anticipated that, through combining magnetic resonance imaging (MRI) and the acoustic studies, a better understanding of the articulatory gestures of these two groups of consonants will be iii obtained. Additionally, the phonetic findings from the MRI and acoustic experiments will be used to suggest an alternative representation of emphatics and gutturals in feature geometry.
Results from the MRI experiment show that pharyngeal width, which varies according to the position of the tongue dorsum, plays a significant role in differentiating between emphatics and plain consonants, but epiglottal width does not have the same significance. Conversely, it was found that narrowed pharyngeal widths, specifically at the upper pharynx level, have no significant role in differentiating gutturals from oral plain consonants – while epiglottal width at the level of the epiglottis does have a significant role in differentiating the two groups of consonants. In contrast, it was concluded that laryngeal level cannot be considered a significant articulatory feature because the natural horizontal location of the larynx represents a real individual difference that works against considering laryngeal level as a universal parameter for the discrimination of emphatics and gutturals from plain consonants.
The results of the acoustic experiment show that emphatics cause significant lowering of F2 on adjacent following vowels while the equivalent plain consonants do not. Concerning F1, the emphatics show notably higher differences in F1 when compared with their plain equivalents. These acoustic properties are due to a consistent narrowing of the upper part of the pharyngeal cavity during the production of emphatics. On the other hand, the various sub-groups of gutturals demonstrate inconsistent effects upon F1 and F2 values except pharyngeals. This sub-group shows a highly significant effect upon raising F1 of all surrounding vowels since they have a clear constriction in the lower part of the pharyngeal cavity.
The combined results of the MRI and acoustic experiments show that emphatics are produced with dorsal retraction of the tongue. This retraction causes consistent narrowing of the upper part of the pharyngeal cavity; however, the tongue root is not involved in this narrowing gesture. Since emphatics have a secondary articulation in the uvular region, they should be described as “uvularized” rather than “pharyngealized”. On the other hand, gutturals are produced with significant narrowing of epiglottal width which is caused by a retracted tongue root but their iv acoustics do not appear to show a common or consistent acoustic property resulting from tongue root retraction. In conclusion, a proposed modification of the Revised Articulator Theory (RAT) was suggested by removing the Tongue Root node from the Guttural root to the Place root. Additionally, it is suggested that gutturals are granted the feature [-ATR] (Advanced Tongue Root) as the phonetic basis for classifying this group of consonants as a natural class in feature geometry.