This report presents a summary of the linguistic research conducted at the Kamehameha Early Education Program (KEEP) during its first five years of operation, as well as a description of relevant linguistic theories. The subjects of the research are the students in the KEEP elementary school (K-3) who were tested twice a year during the five-year period. Two main lines of research are discussed: (1) the development of instruments to measure competence in Standard English (the SERT) and Hawaiian Creole English (the HCERT), and (2) studies of the acquisition and use of specific Standard English (SE) features by Creole-speaking children. The instruments discussed in the first section are described in detail: the technique of elicited information, development of the test items, administration and scoring procedures, and analysis of the results. The studies discussed in the second section were aimed at determining the normative pattern of acquisition of SE features and exploring the effects of various instructional approaches on SE feature acquisition. In this section there is also discussion of studies done with a few supposedly non-verbal children. Conclusions are drawn which deal with the correlation between improvement in Standard English, Creole English, and general language facility and educational development. (Author/AMH)