As an organ unparalleled in anatomical architecture, the tongue has the versatility to effect regional deformations and positional changes with multiple potential degrees of freedom. Despite an abundance of studies on the tongue and its functions, as well as numerous proposed tongue models over the years, much of the anatomical and biomechanical details of the in vivo human tongue remain poorly understood. Physiologically based biomechanical modeling of the tongue in swallowing is the ultimate objective of this protocol. However, before such modeling can be accurately pursued, a substantial database must be established, and several important, unaddressed issues regarding lingual anatomy and biomechanics must be resolved. These issues include: (1) the compressibility of the human tongue and its common, yet untested, reference as a muscular hydrostat; (2) task induced interactions between lingual musculature and vasculature and region-specific vascular demands; (3) changes in lingual fiber orientation, length, and strain distribution as a function of contraction tasks; and (4) effects of normal aging, disease processes, and task training on lingual myoarchitecture as well as the integration between structure and function. Using advanced 3D MRI, Doppler ultrasonography, and other MR imaging techniques (e.g., tagged MRI, diffusion tensor MRI), this protocol proposes to quantitatively address these issues and contribute to a better understanding of the functional biomechanical as well as myoarchitectural intricacies of the in vivo human tongue.