A virtual assistant system includes a mobile device to receive an input command corresponding to a function to be performed at one or more external services, to translate the input command into a semantic atom representing the command, and to transmit the semantic atom, and an assistant server configured to receive the transmitted semantic atom, the assistant server including a plurality of plugins, each plugin corresponding to a respective one of the external services and configured to generate a proprietary language command corresponding to the received semantic atom for each external service in which the function is to be performed.