Rendaku

Rendaku (連濁; Japanese pronunciation: [ɾendakɯ], lit. 'sequential voicing') is a pronunciation change seen in some compound words in Japanese. Rendaku modifies the consonant at the start of the second (or later) part of the compound, replacing a voiceless consonant, such as /k s t h/, with a voiced consonant, such as /ɡ z d b/. For example, the morpheme kami (paper) starts with the voiceless consonant /k/, which is replaced with the corresponding voiced consonant /ɡ/ in the compound word origami, from ori (fold) + kami.

Rendaku is common, but it does not occur in all compound words. A rule known as Lyman's law blocks rendaku when the second element already contains one of the voiced obstruent phonemes /ɡ z d b/, as in the compound word umikaze (sea breeze). Because the second element kaze (wind) contains /z/, its initial consonant /k/ remains voiceless. Rendaku is also blocked almost always when the second element of a compound is a recent loan into Japanese. Furthermore, rendaku may fail to occur even in contexts where no definite blocking factor is present.

In the Japanese writing system, rendaku affects how a morpheme is spelled when using one of the kana syllabaries: it causes the dakuten ("voicing mark", written as ゛) to be added to the upper right corner of the kana character that represents the first consonant and vowel in the second element of the compound. This is seen when comparing the hiragana spelling of kami (かみ) to that of origami (おりがみ): the kana character か (ka) in the first word is replaced with が (ga), with the dakuten, in the second. Rendaku is not marked in writing when a morpheme is spelled using kanji (logographs taken from Chinese characters). For example, kami (paper) is written with the kanji character 紙, which is unchanged when used in the spelling of origami (折り紙).

Linguistically, rendaku involves aspects of both pronunciation (phonology) and word structure (morphology); therefore, it is categorized as a morphophonological phenomenon.