The articulatory organization of the Italian syllable in healthy and pathological speech

The project aims at investigating the articulatory bases of the Italian syllable and at exploring the relevance of the findings in the study of two motor speech disorders, that is Dysarthria, as found in Parkinson’s Disease (PD), and Persistent Developmental Stuttering (PDS). From a theoretical and experimental point of view, the articulatory bases of the Italian syllable remain an open issue as previous phonetic work adopted non-comparable techniques, methods, materials, and made reference to various theories.

The project relies on the use of an articulatory device (AG501) that tracks the 3D position of speech articulators (i.e., tongue, jaw, lips).

 

Four speech phenomena are studied as for their relation with the syllable nucleus: on-/off-glides, geminates vs. singletons contrast, intrinsic geminates and word-initial clusters with and without "impure s". The two articulatory hypotheses put forward on the nature of these phenomena, a "featural" and a "structural" hypothesis, are tested:

 

1) by means of experiments whose design allows to highlight the speakers’ articulatory strategy (e.g., by increasing the syllable prominence, modifying speech rate by asking subjects to speak in time with a metronomic beat and investigating varieties of Italian where allophones differ, requiring different articulatory strategies)

 

2) by observing how strategies change in the case of the selected motor speech disorders.

 

Besides experiments involving healthy subjects as controls, the investigation paradigm is applied to study PDS in people who stutter (PWS) and dysarthria in PD, which show speech disruptions that may be evident at a motor and kinematic level. Understanding the behavior of speech-related effectors will shed light on the articulatory bases of speech units and this may, in turn, clear up the mechanism underlying PD and PDS speech disruptions.