Rendaku or Sequential Voicing in Japanese Phonology

The term rendaku, sometimes translated as sequential voicing, denotes a morphophonemic phenomenon in Japanese. In a prototypical case, an alternating morpheme appears with an initial voiceless obstruent as a word on its own or as the initial element (E1) in a compound but with an initial voiced obstruent as the second element (E2) in a two-element compound. For example, the simplex word /take/ ‘bamboo’ and the compound /take+yabu/ ‘bamboo grove’ (cf. /yabu/ ‘grove’) begin with voiceless /t/, but this morpheme meaning ‘bamboo’ begins with voiced /d/ in /sao+dake/ ‘bamboo (made into a) pole’ (cf. /sao/ ‘pole’). Rendaku was already firmly established in 8th-century Old Japanese (OJ), the earliest variety for which extensive written records exist, and subsequent sound changes have made the alternations phonetically heterogeneous. Many OJ compounds with eligible E2s did not undergo rendaku, and the phenomenon remains pervasively irregular in modern Japanese. There are, however, many factors that promote or inhibit rendaku, and some of these appear to influence native-speaker behavior on experimental tasks. The best known phonological factor is Lyman’s Law, according to which rendaku does not apply to E2s that contain a non-initial voiced obstruent. Many theoretical phonologists endorse the idea that Lyman’s Law is a sub-case of the Obligatory Contour Principle, which rules out identical or similar units if they would be adjacent in some domain. Other well-known factors involve vocabulary stratum (e.g., the resistance to rendaku of recently borrowed E2s) or the morphological/semantic relationship between E2 and E1 (e.g., the resistance to rendaku of coordinate compounds). Some morphemes are idiosyncratically immune to rendaku. Other morphemes alternate but undergo rendaku in some compounds while failing to undergo it in others, even though no known factor is relevant. In addition, many individual compounds vary between a form with rendaku and a form without, and this variability is often not reflected in dictionary entries. Despite its irregularity, rendaku is productive in the sense that it often applies to newly created compounds. Many compounds, of course, are stored (with or without rendaku) in a speaker’s lexicon, but fact that native speakers can apply rendaku not just to existing E2s in novel compounds but even to made-up E2s shows that rendaku as an active process is somehow incorporated into the grammar.