Teaching a complex verbal response to a hearing-impaired girl

A 3-yr-old hearing-impaired girl, who used neither the article "the" nor the auxiliary verb "is" was taught to use these words in describing a picture, initially through imitation and then in response to the command, "Tell me about this". As a result, she was able to use sentences in the present progressive form to describe a number of pictures on which she had received no training. This newly acquired behavior was subsequently extinguished and then reinstated.