Robert Browning - Henry Osopovat   "All the evidence shows that teaching grammatical rules in school has no effect on students' actual performance in speech or writing. In other words, grammatical performance seems to be based on implicit grammatical knowledge, which is unaffected by explicit teaching." Courtney B.Cazden, Language Problems for Education, an article in Language as a Human Problem, ed Einar Haugen & Morton Bloomfield, Lutterworth Press 1975, p.138.