Жапон тіліндегі дыбысталу өзгерісі құбылысы

Morphophonological phenomenon in Japanese language

is a phenomenon in Japanese morphophonology that governs the voicing of the initial consonant of a non initial portion of a compound or prefixed word. In modern Japanese, rendaku is common but at times unpredictable, with certain words unaffected by it. While kanji do not indicate rendaku, it is marked in kana with dakuten (voicing mark).

The voiced obstruent consonants of modern Japanese go back to prenasalized voiced obstruents of Old Japanese. It has been hypothesized that rendaku historically originates from fusion of a nasal derived from the genitive postposition (の) with a following consonant. One theory states that rendaku was originally a way to distinguish compound words from saying a word twice when comparing two words or listing things (compare ひとびと hitobito "people" – with rendaku – versus ひと、ひと hito hito "one person, another person" – without rendaku). Native Japanese words never begin with a voiced obstruent or sibilant (b, d, g, z, etc.) and so rendaku was merely an allophonic detail that did not create ambiguity. However, after the 4th century, Japan started borrowing words and characters from Chinese, which caused the once regular process of rendaku to become less predictable. Since many Chinese words begin with voiced consonants, applying rendaku to those words would cause ambiguity (compare 試験 shiken "examination" with 事件 jiken "incident"). Therefore, compound words consisting of purely Chinese words tend not to exhibit rendaku, unlike compounds consisting of native Japanese words, but there are many exceptions.

Similar to Lyman's Law, it has been found that for some lexical items, rendaku does not manifest if there is a voiced obstruent near the morphemic boundary, including preceding the boundary.

Despite a number of rules which have been formulated to help explain the distribution of the effect of rendaku, there still remain many examples of words in which rendaku manifests in ways currently unpredictable. Some instances are linked with a lexical property as noted above but others may obey laws yet to be discovered. Rendaku thus remains partially unpredictable, sometimes presenting a problem even to native speakers, particularly in Japanese names, where rendaku occurs or fails to occur often without obvious cause. In many cases, an identically written name may either have or not have rendaku, depending on the person. For example, may be read in a number of ways, including both and .

In some cases, voicing of preceding consonants also occurs, as in (細波), which was formerly sasa nami. This is rare and irregular, however.

Native speakers usually (1.3% compared to 10% of all Sino Japanese words) do not apply rendaku to compounds with clusters of voiced nasals and unvoiced obstruents.