Multilingualism enhances cognitive, neuro-linguistic and meta-linguistic development. It is proposed that improved student performance might be achieved if the U.S. educational system mainstreamed foreign language teaching as early as elementary school. The research hypothesis of this quantitative causal-comparative study was therefore that multilingual students should achieve significantly higher scores in standardized tests of basic skills relative to monolingual students. Simple random samples of 500 monolingual and 500 multilingual students in grades 5 through 8 with similar socio-economic status were drawn. There was a significant difference between the combined scores of the monolingual and multilingual students, indicating higher multilingual scores. The results of this and other studies should influence educational policy on language teaching. Urgent action is demanded from educational administrators and curriculum specialists to make foreign language teaching an integral part of the curriculum.