To investigate the linguistic knowledge of Minnesota English teachers, a 100-item questionnaire based on nine basic language concepts was given to 647 elementary and 786 secondary teachers. The concepts were that language is (1) symbolic, (2) highly personal and social, (3) crucial to man's humanity, (4) dynamic, (5) learned, (6) oral, (7) used for a variety of purposes, (8) systematic, and (9) conventional. Results showed that 46.6% of the elementary teachers and 74.4% of the secondary teachers agreed with the linguists on 50% or more of the items. Factors in the backgrounds of both sets of teachers--obtained through the use of a three-part personal data sheet which investigated the teaching situation, teacher preparation, and sources of knowledge about the English language--were found to be significantly related to their agreement with the linguists. Although a comparison of the elementary-teacher results obtained in 1967 with results obtained in a similar study in 1962 revealed that the 1967 respondents were more linguistically knowledgeable than the 1962 respondents, both elementary and secondary English teachers have much to learn about the nature of the English language and language study. (Author/JM)