1. A dialog knowledge acquisition system comprising: a hardware processor and a memory; an input module and an output module controlled by the hardware processor; the memory storing a dialog manager configured to instantiate a persistent interactive personality (PIP) and a dialog graph having a plurality of linked dialog state nodes; the hardware processor configured to execute the dialog manager to: receive a dialog initiation data via the input module; identify a first state node on the dialog graph corresponding to the dialog initiation data; determine a dialog interaction by the PIP based on the dialog initiation data and the first state node; render the dialog interaction via the output module, wherein the output module renders the dialog interaction as at least one of a speech, a facial expression, and a gesture being performed by one of a robot and an avatar; receive a user response corresponding to the dialog interaction via the input module; perform a strict dialog execution policy such that the user response is only mapped to semantically equivalent children of the first state node; perform a relaxed dialog execution policy such that the user response is mapped to the plurality of linked dialog state nodes outside the children of the first state node, upon registering a dialog failure; identify a second state node on the dialog graph based on the dialog initiation data, the dialog interaction, and the user response; and utilize the dialog initiation data, the first state node, the dialog interaction, the user response, and the second state node to train the dialog graph for subsequent dialog interactions by the PIP.