Japanese phonology is the system of sounds used in the pronunciation of the Japanese language. Unless otherwise noted, this article describes the standard variety of Japanese based on the Tokyo dialect.
There is no overall consensus on the number of contrastive individual sounds (phonemes). Common approaches recognize at least 12 distinct consonants (as many as 21 in some analyses) and 5 distinct vowels, . Phonetic length is contrastive for both vowels and consonants, and the total length of Japanese words can be measured in a unit of timing called the mora (from Latin "delay"). Only limited types of consonant clusters are permitted. Japanese speech also has a pitch accent system in which the position or absence of a pitch drop may determine the meaning of a word: (), (), ().
Japanese phonology has been affected by the presence of several layers of vocabulary in the language. In addition to native Japanese vocabulary, Japanese has a large amount of Chinese-based vocabulary (used especially to form technical and learned words, playing a similar role to Latin-based vocabulary in English) and loanwords from other languages. Different layers of vocabulary allow different possible sound sequences (phonotactics).
Lexical strata
Many generalizations about the sound system of Japanese have exceptions when recent loanwords are taken into account. For example, the consonant generally does not occur at the start of native (Yamato) or Chinese-derived (Sino-Japanese) words, but it occurs freely in this position in mimetic and foreign words. Because of exceptions like this, discussions of Japanese phonology often refer to layers, or "strata," of vocabulary. The following four strata may be distinguished:
Yamato
Called or in Japanese, this category consists of inherited native vocabulary. Morphemes in this category show a number of restrictions on structure that may be violated by vocabulary in other layers.
Mimetic
Japanese possesses a variety of mimetic words that make use of sound symbolism to serve an expressive function. Like Yamato vocabulary, these words are also of native origin, and can be considered to belong to the same overarching group. However, words of this type show some phonological peculiarities that cause some theorists to regard them as a separate layer of Japanese vocabulary.
Sino-Japanese
Called in Japanese, words in this stratum originate from several waves of large-scale borrowing from Chinese that occurred from the 6th-14th centuries AD. They comprise 60% of dictionary entries and 20% of ordinary spoken Japanese, ranging from formal vocabulary to everyday words. Most Sino-Japanese words are composed of more than one Sino-Japanese morpheme. Sino-Japanese morphemes have a limited phonological shape: each has a length of at most two moras, which argue reflects a restriction in size to a single prosodic foot. These morphemes represent the Japanese phonetic adaptation of Middle Chinese monosyllabic morphemes, each generally represented in writing by a single Chinese character, taken into Japanese as kanji . Japanese writers also repurposed kanji to represent native vocabulary; as a result, there is a distinction between Sino-Japanese readings of kanji, called On'yomi, and native readings, called Kun'yomi.
The moraic nasal is relatively common in Sino-Japanese, and contact with Middle Chinese is often described as being responsible for the presence of in Japanese (starting from approximately 800 AD in Early Middle Japanese), although also came to exist in native Japanese words as a result of sound changes.
Foreign
Called in Japanese, this layer of vocabulary consists of non-Sino-Japanese words of foreign origin, mostly borrowed from Western languages after the 16th century; many of them entered the language in the 20th century. In words of this stratum, a number of consonant-vowel sequences that did not previously exist in Japanese are tolerated, which has led to the introduction of new spelling conventions and complicates the phonemic analysis of these consonant sounds in Japanese.
Consonants BilabialDental/AlveolarpalatalVelarUvularGlottalSpecial morasNasal () () ()Plosive/Affricate () () () () () Fricative () () () ()() () () () ()Sonorant
Different linguists analyze the Japanese inventory of consonant phonemes in significantly different ways. recognizes only 12 underlying consonants (/m p b n t d s dz r k ɡ h/), whereas recognizes 16, equivalent to Smith's 12 plus the following 4 (/j w ts ɴ/), and recognizes 21, equivalent to Smith's 12 plus the following 9 (/j w ts tɕ (d)ʑ ɕ ɸ N Q/). Consonants inside parentheses in the table can be analyzed as allophones of other phonemes, at least in native words. In loanwords, sometimes occur phonemically.
In some analyses, the glides/semivowels are not interpreted as consonant phonemes. In non-loanword vocabulary, they generally occur only in the sequences and , which are sometimes analyzed as rising diphthongs rather than as consonant-vowel sequences. analyzes the glides as non-syllabic variants of the high vowel phonemes , arguing that the use of vs. may be predictable if both phonological and morphological context is taken into account.
Phonetic notes
Details of articulation
are variously described as lamino-alveolar (), apico-alveolar () or apico-dental (), or simply dental or denti-alveolar. are lamino-alveolar . are lamino(dorso)-alveolopalatal . The affricates are sometimes transcribed broadly as (standing for prepalatal ). The palatalized allophone of before or is also lamino-alveolopalatal or prepalatal, and so can be transcribed as , or more broadly as . reports its place of articulation as dentoalveolar or alveolar. The approximant is traditionally described as velar , labial–velar , or as the semivocalic equivalent of with little to no rounding. However, a 2020 real-time MRI study found that it is likely better described as purely bilabial as there is less velar constriction in the consonant than in the vowel , and thus a transcription of , , or would all be misleading. is before and , and before , coarticulated with the labial compression of that vowel. When not preceded by a pause, it often may be breathy-voiced rather than voiceless . Realization of the liquid phoneme varies greatly depending on environment and dialect. The prototypical and most common pronunciation is an apical tap, either alveolar or postalveolar . Utterance-initially and after , the tap is typically articulated in such a way that the tip of the tongue is at first momentarily in light contact with the alveolar ridge before being released rapidly by airflow. This sound is described variably as a tap, a "variant of ", "a kind of weak plosive", and "an affricate with short friction, ". The apical alveolar or postalveolar lateral approximant is a common variant in all conditions, particularly utterance-initially and before . According to , utterance-initially and intervocalically (that is, except after ), the lateral variant is better described as a tap rather than an approximant. employs a different symbol, , for the lateral tap. The retroflex lateral approximant is also found before . In Tokyo's Shitamachi dialect, the alveolar trill is a variant marked with vulgarity. Other reported variants include the alveolar approximant , the alveolar stop , the retroflex flap , the lateral fricative , and the retroflex stop .
Voice onset time
At the start of a word, the voiceless stops are slightly aspirated—less so than English stops, but more than those in Spanish. Word-medial seem to be unaspirated on average. Phonetic studies in the 1980s observed an effect of accent as well as word position, with longer voice onset time (greater aspiration) in accented syllables than in unaccented syllables., also as cited by .
A 2019 study of young adult speakers found that after a pause, word-initial may be pronounced as plosives with zero or low positive voice onset time (categorizable as voiceless unaspirated or "short-lag" plosives); while significantly less aspirated on average than word-initial , some overlap in voice onset time was observed. A secondary cue to the distinction between and in word-initial position is a pitch offset on the following vowel: vowels after word-initial (but not word-medial) start out with a higher pitch compared to vowels after , even when the latter are phonetically devoiced. Word-medial are normally fully voiced (or prevoiced), but may become non-plosives through lenition.
Lenition
The phonemes have weakened non-plosive pronunciations that can be broadly transcribed as voiced fricatives , although they may be realized instead as voiced approximants . There is no context where the non-plosive pronunciations are consistently used, but they occur most often between vowels: {| cellpadding="5" | > | >
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These weakened pronunciations can occur after a vowel in the middle of a word, or when a word starting with follows a vowel-final word with no intervening pause. found that, as with the pronunciation of as vs. , the use of plosive vs. non-plosive realizations of is closely correlated with the time available to a speaker to articulate the consonant, which is affected by speech rate as well as the identity of the preceding sound. All three show a high (over 90%) rate of plosive pronunciations after or after a pause; after , plosive pronunciations occur at high (over 80%) rates for and , but less frequently for , probably because word-medial after is often pronounced instead as a velar nasal (although the use of here may be declining for younger speakers). Across contexts, generally has a higher rate of plosive realizations than and .
Moraic consonants
Certain consonant sounds are called "moraic" because they count for a mora, a unit of timing or prosodic length. The phonemic analysis of moraic consonants is disputed. One approach, particularly popular among Japanese scholars, analyzes moraic consonants as the phonetic realization of special "mora phonemes" (): a mora nasal , called the hatsuon, and a mora obstruent consonant , called the sokuon. The pronunciation of these sounds varies depending on context: because of this, they may be analyzed as "placeless" phonemes with no phonologically specified place of articulation. A competing approach rejects the transcriptions and and the identification of moraic consonants as their own phonemes, treating them instead as the syllable-final realizations of other consonant phonemes (although some analysts prefer to avoid using the concept of syllables when discussing Japanese phonology).
Moraic nasal
The moraic nasal or mora nasal (hiragana , katakana , romanized as or ) can be interpreted as a syllable-final nasal consonant. Aside from certain marginal exceptions, it is found only after a vowel, which is phonetically nasalized in this context. It can be followed by a consonant, a vowel, or the end of a word:
{| cellpadding="2"
| (hiragana: , three moras long)
| (hiragana: , four moras long)
| (hiragana: , two moras long)
Its pronunciation varies depending on the sound that follows it (including across a word boundary). Before a plosive, affricate, nasal, or liquid, it is pronounced as a nasal consonant assimilated to the place of the following consonant:
{| cellpadding="2" | bilabial before
| velar before
| dorso-palatal before
| lamino-alveolar before
| lamino-alveolopalatal before
| apico-alveolar or postalveolar before | , | ,
Before a vowel, approximant , or voiceless fricative , it is a nasalized vowel or moraic semivowel that can be broadly transcribed as (its specific quality depends on the surrounding sounds). This pronunciation may also occur before the voiced fricatives , although more often, they are pronounced as affricates when preceded by the moraic nasal.