1. A method for analyzing a digital audio signal that is associated with a baby cry, the method comprising the steps of: (a) processing the digital audio signal using a spectral analysis so as to generate a spectral data associated with the digital audio signal; (b) processing the digital audio signal using a time-frequency analysis so as to generate a time-frequency characteristic associated with the digital audio signal; (c) categorizing the baby cry into one of a basic type and a special type with reference to the spectral data associated with the digital audio signal; (d) if the baby cry is categorized into the basic type, determining a basic need with reference to the time-frequency characteristic associated with the digital audio signal and a predetermined lookup table that indicates corresponding relationships between a plurality of time-frequency characteristic candidates and a plurality of basic need candidates; and (e) if the baby cry is categorized into the special type, determining a special need by inputting the time-frequency characteristic associated with the digital audio signal into an artificial neural network so as to generate an output of the special need, the artificial neural network being pre-trained using a plurality of predetermined sets of time-frequency characteristic samples and special need samples respectively as training inputs and training outputs of the artificial neural network.