16. The non-transitory computer-readable medium of claim 12 , wherein the distance statistics relate to similarities in lexical features between the current utterances and at least one previous utterance.
12. The non-transitory computer-readable medium of claim 9 , further comprising receiving contextual information used for detecting the emotion of the user, the contextual information comprising at least one of differential statistics, joint statistics, distance statistics, and statistics collected during a prior dialog between the user and the computing device including (1) differential information of prosodic features, (2) temporal variation of emotion indicators inter-utterance, and (3) temporal variation of emotion indicators intra-utterance.