22. A computer system for executing network applications in which prompts are played at various points of a call flow, each prompt being played in accordance with a prompt definition identifying elements of the prompt, said computer system comprising: a memory containing a plurality of subsets of prompt definitions associated with a particular language, each subset containing prompt definitions for prompts to be played during the call flow, one of said subsets being designated as a base subset and one of said other subsets being designated as an alternate subset; and said computer system being programmed to respond to a request to play a particular prompt at a point in the call flow by first searching the alternate subset to determine whether it contains a prompt definition for the requested prompt, and if so, playing the prompt according to the prompt definition in the alternate subset, but if the alternate subset does not contain a prompt definition for the requested prompt, then searching the base subset for a prompt definition for the requested prompt and playing the prompt according to the prompt definition in the base subset.
22. A computer system for executing network applications in which prompts are played at various points of a call flow, each prompt being played in accordance with a prompt definition identifying elements of the prompt, said computer system comprising: a memory containing a plurality of subsets of prompt definitions associated with a particular language, each subset containing prompt definitions for prompts to be played during the call flow, one of said subsets being designated as a base subset and one of said other subsets being designated as an alternate subset; and said computer system being programmed to respond to a request to play a particular prompt at a point in the call flow by first searching the alternate subset to determine whether it contains a prompt definition for the requested prompt, and if so, playing the prompt according to the prompt definition in the alternate subset, but if the alternate subset does not contain a prompt definition for the requested prompt, then searching the base subset for a prompt definition for the requested prompt and playing the prompt according to the prompt definition in the base subset. 26. The system recited in claim 22 wherein at least one of the prompt definitions in one of the subsets other than the base subset comprises a modified form of a corresponding prompt definition in the base subset.