Contextual Question Answering using Human Chat Logs

A system includes a memory having instructions therein and at least one processor configured to execute the instructions to: receive a natural language question; determine, from a chat log comprising a plurality of chat session logs, a set of chat session logs most relevant to the natural language question; determine a respective plurality of non-overlapping text spans most relevant to the natural language question within each of a respective plurality of conceptual pseudo-documents; determine a conceptual pseudo-document most relevant to the natural language question; extract a question-answer pair most relevant to the natural language question from the most relevant pseudo-document; and convey the most relevant question-answer pair to a user. Each one of the conceptual pseudo-documents corresponds to a respective one of the most relevant chat session logs.