Jerky Movements in Speech Production

The human ability to produce fast fluent speech is astounding. To produce a single word, over 100 muscles must be precisely coordinated, a skill that takes years to master. However, how muscular control is coordinated for different speech sounds, and how it is associated in particular with linguistic functions such as rhythmic, melodic and dynamic features (=prosody), is still largely unexplored in phonetics. 

In this talk I will present a new approach to analyzing articulatory dynamics, characterizing a component that is crucial for revealing the forces that activate the complex interaction of muscle activities: jerk (= rapid movement changes directly linked to muscle activation). 

When there is a change in velocity, we say that an object is accelerating, and when there is a change in acceleration it is jerky. Jerky movements are rapid movement changes of any object – a rollercoaster or the sudden braking of a car – or when an articulator rapidly changes direction as it reaches or leaves a speech posture. In speech, jerky movements connect the speaker to the listener: 1) motor actions are planned by the speaker; 2) muscle activity is coordinated (both agonist and antagonist muscles); 3) jerky movements are produced in articulation; 4) the sound waves contain formant frequency changes; 5) the signal is temporally processed in the auditory system. Jerk is a unique approach to speech production with phonological universal tendencies, which can account for elements of real speech such as prosodic features, and which has possible links to perception by the human sensory systems.