The authors review converging lines of evidence from behavioral, kinematic, and neuroimaging data that point to limitations in speech motor skills in people who stutter (PWS). From their review, they conclude that PWS differ from those who do not in terms of their ability to improve with practice and retain practiced changes in the long term, and that they are less efficient and less flexible in their adaptation to lower (motor) and higher (cognitive–linguistic) order requirements that impact on speech motor functions. These findings in general provide empirical support for the position that PWS may occupy the low end of the speech motor skill continuum as argued in the Speech Motor Skills approach (Van Lieshout, Hulstijn, & Peters, 2004).

Purpose: The purpose of this study was to explore the nature and extent of variability in tongue movement during healthy swallowing as a function of aging and gender. In addition, changes were quantified in healthy tongue movements in response to specific differences in the nature of the swallowing task (discrete vs. sequential swallows). Method: Electromagnetic midsagittal articulography (EMMA) was used to study the swallowing-related movements of markers located in midline on the anterior (blade), middle (body), and posterior (dorsum) tongue in a sample of 34 healthy adults in 2 age groups (under vs. over 50 years of age). Participants performed a series of reiterated water swallows, in either a discrete or a sequential manner. Results: This study shows that age-related changes in tongue movements during swallowing are restricted to the domain of movement duration. The authors confirm that different tongue regions can be selectively modulated during swallowing tasks and that both functional and anatomical constraints influence the manner in which tongue movement modulation occurs. Sequential swallowing, in comparison to discrete swallowing, elicits simplification or down-scaling of several kinematic parameters. Conclusion: The data illustrate task-specific stereotyped patterns of tongue movement in swallowing, which are robust to the effects of healthy aging in all aspects other than movement duration.