This study investigated the effectiveness of a natural environment language training procedure that combined the mand-model procedure and the time delay procedure for the acquisition of noun signs and for the spontaneous use of the signs acquired. One autistic boy, aged 5 years, 4 months with no verbal imitation skills and few movement imitation skills, was taught to shape 16 imitation skills and few movement imitation skills, was taught to shape 16 noun signs by using a simultaneous communication method. The study's results indicate the following changes as training progressed: the child's spontaneous behavior increased, while responses to the teacher's mands decreased. The rate of various response modes changed, with the rate of response with sign alone being high at the beginning of the training and finger-pointing with vocalization being high near the end of the training. The rate of the child's correct signs increased. Interaction patterns between the child and the teacher shifted toward increasing give and take behaviors. The child learned to imitate orally all the Japanese vowels, some diphthongs, and some three-connected vowels. In conclusion, the teaching strategies used showed considerable promise for the acquisition and acceleration of the spontaneous use of noun signs acquired. An abstract is provided in Japanese. (JDD)