15. The computer readable storage medium of claim 13 , wherein deriving the user intent includes: interpreting the text string to derive a plurality of candidate interpretations of user intent; and selecting one of the plurality of candidate interpretations of user intent based on the determination that the pronoun refers to the sender.
15. The computer readable storage medium of claim 13 , wherein deriving the user intent includes: interpreting the text string to derive a plurality of candidate interpretations of user intent; and selecting one of the plurality of candidate interpretations of user intent based on the determination that the pronoun refers to the sender. 16. The computer readable storage medium of claim 15 , wherein selecting one of the plurality of candidate interpretations of user intent includes determining whether the one of the plurality of candidate interpretations of user intent satisfies a predetermined confidence threshold.