THE WORD ASSOCIATIONS OF URBAN SLUM CHILDREN, BOTH NEGRO AND WHITE, WERE STUDIED TO DETERMINE WHAT IMPACT EXTREME SOCIOECONOMIC STATUS DIFFERENCES HAVE ON LANGUAGE DEVELOPMENT. THIS STUDY OF CHILDREN FROM THE LOWEST EXTREME OF THE SOCIOECONOMIC SCALE WAS MADE AS A FOLLOWUP TO AN EARLIER STUDY OF CHILDREN REPRESENTING VARIOUS CULTURAL AND SOCIOECONOMIC CLUSTERS. DATA WERE GATHERED FROM 541 CHILDREN ENROLLED IN PUBLIC ELEMENTARY SCHOOLS IN BALTIMORE CITY, MARYLAND BECAUSE IT HAD BEEN OBSERVED PREVIOUSLY THAT RACE-OF-INTERVIEWER AFFECTED THE CHILDREN'S RESPONSES, THE ENTIRE DESIGN WAS REPLICATED FOUR TIMES (NEGRO INTERVIEWER WITH WHITE CHILDREN, NEGRO INTERVIEWER WITH NEGRO CHILDREN, WHITE INTERVIEWER WITH WHITE CHILDREN, AND WHITE INTERVIEWER WITH NEGRO CHILDREN). NO CHILD WAS INTERVIEWED MORE THAN ONCE. THE PRINCIPLE MEASURE OF LINGUISTIC DEVELOPMENT WAS THE NUMBER OF WORD RESPONSES THAT MATCHED PREVIOUSLY DETERMINED PARADIGMS, SUCH AS, THE RESPONSE TO "GO" IS "RUN." FIRST-GRADE WHITE SLUM CHILDREN WERE FOUND TO BE MORE ADVANCED LINGUISTICALLY THAN SUBURBAN CHILDREN OF SIMILAR IQ. FURTHER, EVEN THOUGH NEGRO FIRST-GRADE SLUM CHILDREN ARE NOT AS ADVANCED AS WHITE SLUM CHILDREN, THEY ARE PROBABLY AS MATURE LINGUISTICALLY AS WHITE SUBURBAN CHILDREN OF THE SAME INTELLIGENCE LEVEL. THE RELATIVE ADVANCEMENT OF FIRST-GRADE SLUM CHILDREN DISAPPEARS BY THIRD GRADE, AND THEY LAG BEHIND SUBURBAN CHILDREN AT AGES 8 AND OVER. THIS SUGGESTS THAT THE DEGREE OF URBANIZATION MAY STRONGLY AFFECT VERBAL DEVELOPMENT. IN ANALYSIS OF THE RACE-OF-INTERVIEWER FACTOR, IT WAS FOUND THAT MORE MATURE RESPONSES ARE MADE BY CHILDREN WHEN THEY ARE RESPONDING TO AN INTERVIEWER OF A DIFFERENT RACE THAN THEIR OWN. RELATED REPORTS ARE AA 000 047 AND AA 000 048. (AL)