This investigation studied (1) the acquisition and proportion of correct usage of consonants of Japanese and American children, (2) the consonant substitutions of children developing normal language and of children with articulation problems, and (3) confusion in adults' recall of consonants. A system of distinctive features (gravity, diffuseness, stridency, nasality; continuancy, and voicing) was used to describe the behavior observed. It was found that features played a hierarchical role in terms of acquisition and proportion of correct usage, as well as in terms of resistance to perceptual and productive confusion. The features also played differing roles depending on the task, the age of the subjects, and their status in learning the sound system of their language. (Author/DO)