Virtual assistants (VAs) help users or enterprises with a set of tasks previously only made possible by humans. VAs use semantic and deep learning (such as deep neural networks [DNNs], natural language processing, prediction models, recommendations and personalization) to assist people or automate tasks. VAs listen to and observe behaviors, build and maintain data models, and predict and recommend actions. VAs can be deployed in several use cases, including virtual personal assistants, virtual customer assistants and virtual employee assistants.