10. A system comprising: one or more processors; and memory communicatively coupled to the one or more processors and storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising: causing a virtual assistant to carry out a conversation with a user; receiving user input during the conversation; determining one or more concepts for the user input by executing the instructions to: access features of a knowledge base stored in the memory, the features organized to trigger outputs according to units of vocabulary patterns arranged in the features, wherein the vocabulary patterns are stored in the memory with respective labels; substituting portions of the user input with sets of terms bearing corresponding labels that refer back to the respective labels of the knowledge base; matching the respective labels and the corresponding labels to identify a digital response to the speech input; causing the digital response to be presented to the user in real-time via the virtual assistant causing a task to be performed at least in part by the virtual assistant.
10. A system comprising: one or more processors; and memory communicatively coupled to the one or more processors and storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising: causing a virtual assistant to carry out a conversation with a user; receiving user input during the conversation; determining one or more concepts for the user input by executing the instructions to: access features of a knowledge base stored in the memory, the features organized to trigger outputs according to units of vocabulary patterns arranged in the features, wherein the vocabulary patterns are stored in the memory with respective labels; substituting portions of the user input with sets of terms bearing corresponding labels that refer back to the respective labels of the knowledge base; matching the respective labels and the corresponding labels to identify a digital response to the speech input; causing the digital response to be presented to the user in real-time via the virtual assistant causing a task to be performed at least in part by the virtual assistant. 11. The system of claim 10 , wherein the task comprises providing content to the user.