The purposes of this study are stated to be twofold: (1) to determine the relative effects of the native language and black dialect influences on the oral English performance of Puerto Rican pupils in mainland schools and (2) to assess the relationship of these sources of linguistic interference with aural ability in English, reading ability in English, and time in mainland schools. The oral repetition technique is used with 80 Puerto Rican children enrolled in grades 2-4 in a predominantly Puerto Rican bilingual school. Findings indicate a significant positive correlation between degrees of black dialect interference and time in mainland schools. Significant inverse correlations are indicated between degree of black dialect interference and reading ability in English and between degree of Spanish interference and aural ability in English. Time in mainland schools is said to be significantly related to aural ability in English but not to reading ability. A relationship approaching significance between the degree of native language interference and reading ability in English is considered to indicate a need to explore more systematic approaches to the teaching of English to Spanish speaking students. (Author/AM)