rendaku

Rendaku, or 連濁, is a phonological process in Japanese in which the initial consonant of the second element of a compound or multi-morpheme word becomes voiced. In practice, this means that a typically voiceless onset such as k, s, t, or h may change to its voiced counterpart g, z, d, or b when the second element begins with one of those consonants. Rendaku is a productive feature of standard Japanese, but it is not completely predictable and there are many irregularities.

A well-known example is tegami, meaning letter, formed from te (hand) and kami (paper). The second element’s initial k changes to g, yielding tegami. Another illustrative case is hanafuda, a traditional card game; although hana (flower) and fuda (card) could in principle yield a voiced onset, the standard pronunciation remains hanafuda, showing that rendaku does not always apply.

Rendaku tends to occur in native Japanese compounds and is less common in Sino-Japanese (go-on or kan-on) compounds, where voicing is often blocked or irregular. The process is influenced by a variety of factors, including lexicalized forms, historical sound changes, and phonotactic constraints. Because many exceptions are lexicalized, learners often rely on memorization or dictionary entries rather than a single rule set.

Historically, rendaku emerges from early voicing processes across morpheme boundaries and has since become an entrenched aspect of the language in many compounds. While it can aid pronunciation and rhythm, it also contributes to the complexity of Japanese spelling and pronunciation for non-native learners.