SETS OF ORTHOGRAPHIC PATTERNS BASED ON AN ANALYSIS OF THE SPELLINGS AND PRONUNCIATIONS OF THE 20,000 MOST COMMON ENGLISH WORDS ARE ORGANIZED AND PRESENTED. TWO BASIC SETS OF PATTERNS ARE DISCUSSED. THE FIRST PERTAINS TO THE INTERNAL STRUCTURE OF THE ORTHOGRAPHY--THE CLASSES OF LETTERS (GRAPHEMES) AND THE ALLOWABLE SEQUENCES OF THESE LETTERS (GRAPHOTACTICS). THE SECOND SET CONTAINS THOSE PATTERNS WHICH RELATE SPELLING TO SOUND. EACH FUNCTIONAL ORTHOGRAPHIC UNIT IS CLASSED AS A RELATIONAL UNIT OR A MARKER, DEPENDING UPON WHETHER IT RELATES TO SOUND ITSELF OR MARKS THE FUNCTIONING OF SOME OTHER UNIT. RELATIONAL UNITS ARE MAPPED FIRST ONTO AN INTERMEDIATE (MORPHOPHONEMIC) LEVEL BY ONE SET OF RULES AND THEN INTO SOUND BY ANOTHER SET OF RULES, THUS ALLOWING A CLEAR SEPARATION OF RULES BASED PRIMARILY UPON ORTHOGRAPHIC CONSIDERATIONS FROM THOSE BASED PRIMARILY UPON MORPHEMIC AND PHONEMIC CONSIDERATIONS. THIS ARTICLE APPEARED IN THE "READING RESEARCH QUARTERLY," VOLUME 2, NUMBER 3, SPRING 1967. (AUTHOR)