The human voice is able to produce a very rich set of different sounds, making it the single most important channel for communication human-to-human, and also potentially for human-computer interaction. Spoken communication can be thought of as a stack of layered transport protocols that includes language, speech, voice, and sound. In this Dagstuhl seminar, we will be concerned with the voice and its function as a transducer from neurally encoded speech patterns to sound. This very complex mechanism remains insufficiently explained both in terms of analysing voice sounds, as for example in medical assessment of vocal function, and of simulating them from first principles, as in talking or singing machines.