Link to this article: http://journals.cambridge.org/abstract_S0022226714000024How to cite this article: AKIKO NAGANO and MASAHARU SHIMADA (2014). Morphological theory and orthography: Kanji as a representation of lexemes .Orthography has been given marginal status in theoretical linguistics, but it can offer 'visible' insights into the invisible mechanisms of grammar. Japanese kanji graphs, Chinese characters used to write Japanese, provide an excellent illustration of this perspective. Our core claim is that the kanji orthography reflects the working of lexeme-based morphology in Japanese grammar. Specifically, we show how the lexeme-based morphological framework developed by Mark Aronoff and Martin Maiden can explain apparently cumbersome and inefficient properties of the kanji usage, its dual pronunciation in particular. Among the findings of this study are the following: (i) the underlying mechanism of the kanji's dual pronunciation is suppletion, native and Sino-Japanese synonyms working as morphomic stems of the same paradigm; (ii) this suppletion emerged and developed as a paradigmatic strategy of synonymy avoidance; and (iii) the large-scale suppletive morphology has long been retained in Japanese because it has served advantageous functions in the maintenance of lexemic isomorphism and in lexical stock expansion. Our findings shed an entirely new light on the bafflingly complex nature of Japanese orthography; it is the complexity of morphology, a grammatical module that is deemed to be the locus of language-specificity.[] The original manuscript of this paper has been drastically revised following three anonymous Journal of Linguistics referees' comments and suggestions. We would like to express our deep gratitude to each of them for carefully reading our manuscript and generously providing us with ideas and data for improvement. Also, we are grateful for the comments from the participants of the ICHL workshop 'The Role of Autonomous Morphology in Language Change' (organised by Martin Maiden and John Charles Smith, July , Osaka), where the initial idea of this paper was presented. Our special thanks go to Ewa Jaworska for invaluable editorial support. Needless to say, we are solely responsible for the contents of this paper. This study is financially supported by the Japan Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for Scientific Research (C), No. ). Abbreviations used in this paper are: = second person, A = adjective, ABL = ablative, ACC = accusative, Adv = adverbial, AGT = agent, C = consonant, Comp = compound, CONCL = conclusive, GEN = genitive, HON = honorific, IMP = imperative, Infl = inflection, INF = infinitive, L = lexeme, NOM = nominative, P = stem, P Adv = adverbial stem, P Comp = compounding stem, P Infl = inflectional stem, PL = plural, PRT = particle, SJ = Sino-Japanese, SG = singular, V= vowel, VOC = vocative, WFA = word-forming affix.