Key points are not available for this paper at this time.
Wick Miller, Susan Ervin, The Development of Grammar in Child Language, Monographs of the Society for Research in Child Development, Vol. 29, No. 1, The Acquisition of Language: Report of the Fourth Conference Sponsored by the Committee on Intellective Processes Research of the Social Science Research Council (1964), pp. 9-34
Miller et al. (Wed,) studied this question.