The study was conducted with the understanding that bilingual Navajo Indian students attempting to get an education in the public school system are faced with learning to read the English language under the conventional method. As stated, the primary purpose of this study was to determine if the Indian and non-Indian children in grades 4, 5, and 6 of the San Juan County School District, Utah, could increase their reading vocabulary using 6 conventional basal readers and accompanying dictionaries, the "Little Dictionaries for Vocabulary and Idioms," during the school year 1969-70. These investigator-constructed dictionaries contained English definitions of every idiom and vocabulary item in the basal readers that the researcher deemed questionable in terms of understanding by a bilingual student. Results of the pre- and post-test were statistically compared using the t-ratio. General findings were that grades 5 and 6 of the experimental Indian group showed significant gains in vocabulary skills; grade 4 Indian students in the experimental groups gained higher than grade 4 Indians in the control group; and grade 4 non-Indians in the control group gained significantly higher than Indians in the same group. Recommendations are included for replication and further study of the problem. (EL)