Frontmatter -- PREFACE -- TABLE OF CONTENTS -- LIST OF TABLES -- 1 THE PROBLEM AND THE DATA -- 2 SINGLE-WORD UTTERANCES AND GRAMMAR -- 3 SINGLE-WORD UTTERANCES ARE NOT SENTENCES -- 4 DEVELOPMENTAL CHANGE IN THE USE OF SINGLE-WORD UTTERANCES -- 5 CONCEPTS, WORDS, AND SENTENCES -- REFERENCES -- APPENDIX -- SUBJECT INDEX -- NAME INDEX