12. A non-transitory, tangible, computer-readable storage medium containing a program of instructions that cause a computer system running the program of instructions to: receive a text specifying words to be spoken by a virtual character; receive an audio file corresponding to the text; extract metaphoric elements, discourse elements, reference elements, valence elements, or a combination thereof from the text; extract agitation moments, speech disfluency, or both from the audio file; generate one or more mental state indicators based on the metaphoric elements, the discourse elements, the reference elements, the valence elements, or the combination thereof and the agitation moments, the speech disfluency, or both; map each of the one or more mental state indicators to a behavior that the virtual character should display with nonverbal movements that convey the mental state indicators; and generate a set of instructions for the nonverbal movements based on the behaviors.
12. A non-transitory, tangible, computer-readable storage medium containing a program of instructions that cause a computer system running the program of instructions to: receive a text specifying words to be spoken by a virtual character; receive an audio file corresponding to the text; extract metaphoric elements, discourse elements, reference elements, valence elements, or a combination thereof from the text; extract agitation moments, speech disfluency, or both from the audio file; generate one or more mental state indicators based on the metaphoric elements, the discourse elements, the reference elements, the valence elements, or the combination thereof and the agitation moments, the speech disfluency, or both; map each of the one or more mental state indicators to a behavior that the virtual character should display with nonverbal movements that convey the mental state indicators; and generate a set of instructions for the nonverbal movements based on the behaviors. 15. The medium of claim 12 , wherein the program of instructions that also cause the computer system running the program of instructions to: produce a set of instructions for lip sync movements of the virtual character based on the text and the audio file.