Rendaku is a phenomenon in Japanesemorphophonology that governs the voicing of the initial consonant of the 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, they are marked in kana with dakuten.
Examples
Rendaku can be seen in the following words: In some cases, rendaku varies depending on syntax. For instance, the suffix, from, is pronounced as following the perfective verb, as in, but is pronounced as when following a noun, as in or, semantically differently – more concretely –. Rendaku occurs not only on single-root morphemes, but also "multi-root" morphemes, those that are themselves composed of smaller morphemes. These morphemes may also be of Chinese origin or even of non-Literary-Chinese origin rather than strictly native. Notice that for certain morphemes that begin with the morae chi and tsu, their rendaku forms begin with the morae ji and zu, spelledprecisely in hiragana as ぢ and づ, which explains the use of these kana in contrast to the identically pronounced じ and ず. This isn't a hard and fast rule, however, because it's relaxed in certain older compounds or names, especially those that are so consolidated that they could hardly be recognized as compounds anymore, but rather, as single words themselves. Rendaku occurs not only in compound nouns, but also in compounds with adjectives, verbs or continuative/nominal forms of verbs.
Properties blocking ''rendaku''
Research into defining the range of situations affected by rendaku has largely been limited to finding circumstances which cause the phenomenon not to manifest.
Lyman's Law
Lyman's Law states that there can be no more than one voiced obstruent within a morpheme. Therefore, no rendaku can occur if the second element contains a voiced obstruent. This is considered to be one of the most fundamental of the rules governing rendaku. Although this law is named after Benjamin Smith Lyman, who independently propounded it in 1894, it is really a re-discovery. The Edo period linguists Kamo no Mabuchi and Motoori Norinaga separately and independently identified the law during the 18th century.
Lexical properties
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. Some lexical items tend to resist rendaku voicing regardless of other conditions, while some tend to accept it. Rendaku usually only applies to native Japanese words, but it also occurs infrequently in Sino-Japanese words especially where the element undergoing rendaku is well integrated. It is even rarer to find rendaku among words of foreign origin, unless the loanword has become completely absorbed into Japanese:
Semantics
Rendaku also tends not to manifest in compounds which have the semantic value of "X and Y" : Compare this to yama + kawa > yamagawa "mountain river".
Branching constraint
Rendaku is also blocked by what is called a "branching constraint". In a right-branching compound, the process is blocked in the left-branching elements: but
Further considerations
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.
Voicing of preceding consonant
In some cases, voicing of preceding consonants also occurs, as in, which was formerly sasa-nami. This is rare and irregular, however.
