are a set of four specific

kana The term may refer to a number of syllabaries used to write Japanese phonological units, morae. Such syllabaries include (1) the original kana, or , which were Chinese characters (kanji) used phonetically to transcribe Japanese, the most pr ...

, じ, ぢ, ず, づ (in the

Nihon-shiki romanization Nihon-shiki ( ja, 日本式ローマ字, "Japan-style," romanized as ''Nihonsiki'' in the system itself), is a romanization system for transliterating the Japanese language into the Latin alphabet. Among the major romanization systems for Japan ...

system: ''zi'', ''di'', ''zu'', ''du''), used in the

Japanese writing system The modern Japanese writing system uses a combination of logographic kanji, which are adopted Chinese characters, and syllabic kana. Kana itself consists of a pair of syllabaries: hiragana, used primarily for native or naturalised Japanese wo ...

. They historically represented four distinct voiced

morae A mora (plural ''morae'' or ''moras''; often symbolized μ) is a basic timing unit in the phonology of some spoken languages, equal to or shorter than a syllable. For example, a short syllable such as ''ba'' consists of one mora (''monomoraic'') ...

(syllables) in the Japanese language. However, most dialects, such as Standard Japanese-speakers, have undergone mergers and now pronounce two sounds.

Modern sound usage in various dialects

Most of the far northern dialects (

Tōhoku dialect The , commonly called 東北弁 ''Tōhoku-ben'', is a group of the Japanese dialects spoken in the Tōhoku region, the northeastern region of Honshū. Toward the northern part of Honshū, the Tōhoku dialect can differ so dramatically from standa ...

s and Hokkaidō) and far southern dialects (notably

Okinawan Japanese is the Japanese language as spoken by the people of Okinawa Islands. Okinawan Japanese's accents and words are influenced by the traditional Okinawan and Kunigami languages. Okinawan Japanese has some loanwords from American English due to t ...

) and the

Ryukyuan languages The , also Lewchewan or Luchuan (), are the indigenous languages of the Ryukyu Islands, the southernmost part of the Japanese archipelago. Along with the Japanese language and the Hachijō language, they make up the Japonic language family. Al ...

(the other

Japonic languages Japonic or Japanese–Ryukyuan, sometimes also Japanic, is a language family comprising Japanese, spoken in the main islands of Japan, and the Ryukyuan languages, spoken in the Ryukyu Islands. The family is universally accepted by linguists, and ...

) have also mostly merged the four sounds to one sound. However, a few dialects, mainly around

Shikoku is the smallest of the four main islands of Japan. It is long and between wide. It has a population of 3.8 million (, 3.1%). It is south of Honshu and northeast of Kyushu. Shikoku's ancient names include ''Iyo-no-futana-shima'' (), '' ...

and

Kyushu is the third-largest island of Japan's five main islands and the most southerly of the four largest islands ( i.e. excluding Okinawa). In the past, it has been known as , and . The historical regional name referred to Kyushu and its surroun ...

in the southwest, still distinguish three or even all four sounds. In the current

Tokyo dialect The Tokyo dialect () is a variety of Japanese language spoken in modern Tokyo. As a whole, it is generally considered to be Standard Japanese, though specific aspects of slang or pronunciation can vary by area and social class. Overview Tr ...

, the base of the modern standard language, as well as in the widely spoken

Kansai dialect The is a group of Japanese dialects in the Kansai region (Kinki region) of Japan. In Japanese, is the common name and it is called in technical terms. The dialects of Kyoto and Osaka are known as , and were particularly referred to as suc ...

, only two sounds are distinguished, as is represented in the Hepburn (''ji'', ''ji'', ''zu'', ''zu'') and

Kunrei is the Cabinet-ordered romanization system for transcribing the Japanese language into the Latin alphabet. Its name is rendered ''Kunreisiki rômazi'' in the system itself. Kunrei-shiki is sometimes known as the Monbushō system in English bec ...

(''zi'', ''zi'', ''zu'', ''zu'') romanization systems.

Modern kana usage

The spelling differences between the four kana were retained well into the mid-20th century, long after the merger of the different sounds that they had represented. Two distinct morae remain in most dialects of the mainland, such as in Tokyo. Shortly after World War II ended, the discrepancy between kana orthography and pronunciation was rectified as part of a general orthographic reform, the

Gendai Kanazukai is the present official ''kanazukai'' (system of spelling the Japanese syllabary). Also known as , it is derived from historical usage. History As long ago as the Meiji Restoration, there had been dissatisfaction regarding the growing discr ...

, or modern kana orthography. Under the new

orthographic rules Morphological parsing, in natural language processing, is the process of determining the morphemes from which a given word is constructed. It must be able to distinguish between orthographic rules and morphological rules. For example, the word 'fo ...

, only the two kana じ ''zi'' and ず ''zu'' are to be used, with two notable exceptions: # When a word exhibits sequential voicing, or

rendaku 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 una ...

, as a result of compounding, a second morpheme that would otherwise begin with the kana つ ''tu'' or ち ''ti'' in isolation (神無月　かんなづき ''kannaduki'' for which 月 in isolation is written つき ''tuki''). # When the kana つ ''tu'' or ち ''ti'' is repeated and voiced in a word (続くつづく ''tuduku''). An exception was permitted for regions that pronounced the four kana as three or four distinct sounds. After a 1986 update to the Gendai Kanazukai, the exception was replaced with a statement that the unified spelling was to be primarily used, but etymologically-correct spellings would still be permitted.

Modern regional variants

The following table shows some of the different realizations and mergers of the Yotsugana characters throughout Japan:

References

{{Japanese romanization Japanese dialects Japanese phonology Kana Japanese orthography Japanese writing system