1. A system with a platform for building a dialog-state specific multi-turn contextual language understanding system for an application, the system comprising: at least one processor; and a memory for storing and encoding computer executable instructions that, when executed by the at least one processor is operative to: receive information from a builder for building a single-shot language understanding model, wherein the information includes any slots and entities necessary for performing a task in one turn of a dialog; configure the single-shot language understanding model based on the information; constrain a decoding of the single-shot language understanding model to output only dialog-state specific slots and dialog-state specific entities for each determined dialog-state based on a dialog-state dependent semantic schema; implement a constrained single-shot language understanding model to form the dialog-state specific multi-turn contextual language understanding system; and analyze a received utterance from a user with the multi-turn contextual language understanding system.