On the linguistic effects of articulatory ease, with a focus on sign languages
Spoken language has a well-known drive for ease of articulation, which Kirchner (1998, 2004) analyzes as reduction of the total magnitude of all biomechanical forces involved. We extend Kirchner’s insights from vocal articulation to manual articulation, with a focus on joint usage, and we discuss ways that articulatory ease might be realized in sign languages. In particular, moving more joints and/or joints more proximal to the torso results in greater mass being moved, and thus more articulatory force being expended, than moving fewer joints or moving more distal joints. We predict that in casual conversation, where articulatory ease is prized, moving fewer joints should be favored over moving more, and moving distal joints should be favored over moving proximal joints. We report on the results of our study of the casual signing of fluent signers of American Sign Language, which confirm our predictions: in comparison to citation forms of signs, the casual variants produced by the signers in our experiment exhibit an overall decrease in average joint usage, as well as a general preference for more distal articulation than is used in citation form. We conclude that all language, regardless of modality, is shaped by a fundamental drive for ease of articulation. Our work advances a cross-modality approach for considering ease of articulation, develops a potentially important vocabulary for describing variations in signs, and demonstrates that American Sign Language exhibits variation that can be accounted for in terms of ease of articulation. We further suggest that the linguistic drive for ease of articulation is part of a broader tendency for the human body to reduce biomechanical effort in all physical activities.