A computer-implemented method identifies a spoken audio signal representing speech of a person and estimates a physiological state of the person based on the spoken audio signal. For example, the method may identify articulatory patterns (such as landmarks) in the speech and estimate the person's physiological state based on those articulatory patterns. The method may estimate, for example, the amount of time the person has been without sleep. The method may produce the physiological state estimate without performing speech recognition on the spoken audio signal. The method may produce the physiological state estimate in real-time.