The research reported in these papers covers a variety of communication problems. The first paper covers research on sound navigation by the blind and involves echo perception research and relevant aspects of underwater sound localization. The second paper describes a research program in acoustic phonetics and concerns such related issues as consonant-vowel transitions in the speech of deaf adults and the intelligibility of whispered speech in a tone language. The third paper studies some of the basic problems in data-sharing among information systems and in ambiguity resolution and feedback utilization in man-machine communication. The final paper deals with studies in psychoacoustics and describes research in binaural hearing and two sets of interactions involving the interaural differences required to localize a sound source. (VM)