7. The system of claim 5 , wherein the module that controls the processor to build a series of NLU models further keeps a fixed text set and uses all other data for training.
5. A system for generating a natural language understanding (NLU) model for use in a spoken dialog service, the system having a processor and comprising: (a) a module that controls the processor to build a first NLU model using sample utterances from a labeling guide, hand crafted rules and labeled utterances of available dialogs; (b) a module that controls the processor to test the performance of the first NLU model using sample utterances in the labeling guide; and (c) a module that controls the processor to build a series of NLU models and evaluate the performance of the series of NLU models as labeled data becomes available by: (i) adding a previous batch of labeled data to training data; and (ii) using a new batch of labeling data as test data to generate the series of NLU models with training data that increases constantly.