This paper deals with two experiments whose purposes are to investigate the linguistic competence of young children and their receptivity to adult speech. In the free response experiment, imperative sentences were presented to 1 1/2- to 2 1/2-year-olds. The sentences were minimal (a single noun), telegraphic, or full adult sentences. The youngest children were most responsive to minimal or telegraphic form, while the oldest responded to full sentences. The conclusion is that there is a period when language input and output is telegraphic and a slightly later stage when children understand full adult speech as input but when their output is still telegraphic. They tend not to listen to adult speech beginning with unfamiliar words. In the repitition experiment, grammatical and ungrammatical sentences were presented for immediate repetition to eighteen 3- and 4-year-olds. Responses contained errors in relation to the complexity of sentence structure and less accurate identification of ungrammatical sentences. The child corrects ungrammatical sentences in ratio to his familiarity with the structure. When he cannot identify a structure, he tends to give a simpler structure rather than a confused version of the difficult one. It is suggested as a result of the two experiments that children listen selectively to adult speech and that repetition is useful in investigating language competence. (DO)