Ease of articulation.
D000328:Adult; D000367:Age Factors; D001307:Auditory Perception; D002675:Child, Preschool; D006801:Humans; D007804:Language Development; D008046:Lip / Q000502:physiology; D008334:Mandible / Q000502:physiology; D009043:Motor Activity; D009119:Muscle Contraction; D010614:Pharynx / Q000502:physiology; D010700:Phonetics; D005082:Physical Exertion; D013060:Speech; D014059:Tongue / Q000502:physiology; D014831:Voice