1. A computer-implemented voice user interface system, comprising: an application program interface that supports configuration of a voice user interface that mixes different types of audible dialog prompts, and wherein the application program interface comprises: a first dialog container that includes information for activating, in a predetermined sequence, audible dialog prompts that correspond to a collection of audible dialog elements assigned to the first dialog container, the predetermined sequence being at least partially determined by semantics-driven audible dialog functionality applied by the first dialog container to said collection of audible dialog elements assigned to the first dialog container; a second dialog container that includes information for activating, in a predetermined order, audible dialog prompts that correspond to a collection of audible dialog elements assigned to the second dialog container, the predetermined order being at least partially determined by state-driven audible dialog functionality applied by the second dialog container to said collection of audible dialog elements assigned to the second dialog container; a particular audible dialog element that corresponds to a particular audible dialog prompt, wherein the particular audible dialog element having different property setting requirements depending upon whether included in the collection of audible dialog elements assigned to the first dialog container or the set of audible dialog elements assigned to the second dialog container; and a computer processor that is a component of a computing device, wherein the computer processor processes an implementation of the application program interface and provides a corresponding implementation of the voice user interface by outputting, to a user of the voice user interface system, said audible dialog prompts that correspond to the collection of audible dialog elements assigned to the first dialog container and said audible dialog prompts that correspond to the collection of audible dialog elements assigned to the second dialog container.