Abstract: Methods and apparatuses are described for integrating common and context-specific natural language understanding (NLU) processing in a virtual assistant application. A server identifies a common NLU processing unit comprising (i) a common NLU classification model and (ii) a common response library comprising common responses. The server builds a combined NLU processing unit based upon the common NLU classification model and a context-specific NLU classification model, the combined NLU processing unit comprising (i) a combined NLU classification model trained using the common NLU training data and context-specific NLU training data, (ii) the common response library and (iii) a context-specific response library comprising context-specific responses. The server generates a response to an input utterance by determining a user intent associated with the input utterance using the combined NLU classification model, locating a response associated with the user intent in one or more of the libraries.