1. A system for delivering advanced natural language applications, the system comprising: a dialog interface module operating on a server computer and adapted for exchanging information with a user via a network; a natural language interaction engine operating on a server computer and coupled to the dialog interface module, for interpreting a received user request; a solution data repository component operating on a server computer and coupled to the natural language interaction engine, the solution data repository comprising a plurality of hierarchical ontological domain models, a plurality of hierarchical language models comprising a preconfigured, hierarchical arrangement of language objects, a plurality of language recognition rules expressed in terms of elements of the plurality of hierarchical language models, and a plurality of flow elements and rules for managing interactions with users; and an interface software module coupled to the natural language interaction engine and adapted to exchange data or commands with a plurality of external software services over a network; wherein upon receipt of a request from a user via a network, the dialog interface module preprocesses the request and transmits it to the natural language interaction engine; and wherein the natural language interaction engine interprets the request to determine one or more semantic meanings or user intents associated with the request, using the plurality of language recognition rules, the plurality of hierarchical ontological domain models, and the plurality of flow elements stored in the solution data repository; and further wherein, based at least on the one or more semantic meanings or user intents, the natural language interaction engine forms an appropriate response and delivers the response to the dialog module, which uses one or more output means of the computing device to provide a response to the user via a network, or takes an appropriate automated action in response to the request.