An articulatory study of differences and similarities between stuttered disfluencies and non-pathological disfluencies

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While stuttering-like disfluencies have long interested researchers, little is known about their articulatory realisation. Yet, such a description seems crucial in order to better understand the differences between stuttering-like and other disfluencies, and their underlying motor mechanisms. Hence, we aimed to compare the articulatory supraglottic activity in stuttered disfluencies with non-pathological disfluencies by using Electromagnetic Articulography (EMA) data. To achieve this comparison, two criteria were used for the description of articulatory activity during the disfluency. The first focused on the characterisation of the movements observable during the disfluency. This criterion gives an indication of the presence or absence of articulatory movement as well as interarticulator coupling. The second criterion provided information on the retention and anticipation of the sound preceding and following the disfluency. In order to strengthen our analysis, both criteria were examined using two complementary methodologies. The first was an expert-based analysis, while the second used a set of metrics based on velocity and acceleration. These analyses were conducted independently, and the final results of our study corresponded to the conclusions of the comparison of both methodology results. The results we obtained show that stuttered disfluencies and non-pathological disfluencies do have common characteristics. However, stuttered disfluencies and non-pathological disfluencies produced by Persons Who Stutter (PWS) present some particularities, mainly in terms of retention and anticipation, and the presence of spasmodic movements. Results are discussed in the light of different models of stuttering.