The is a Japanese symbol in the form of a small hiragana or katakana , as well as the various consonants represented by it. In less formal language, it is called or , meaning "small ". It serves multiple purposes in Japanese writing.
In both hiragana and katakana, the appears as a reduced in size:
The main use of the is to mark a geminate consonant, which is represented in most romanization systems by the doubling of the consonant, except that Hepburn romanization writes a geminate ch as tch. It denotes the gemination of the initial consonant of the symbol that follows it.
Examples:
The sokuon never appears at the beginning of a word or before a vowel (a, i, u, e, or o), and rarely appears before a syllable that begins with the consonants n, m, r, w, or y. (In words and loanwords that require geminating these consonants, , , , , and are usually used, respectively, instead of the sokuon.) In addition, it does not appear before voiced consonants (g, z, d, or b), or before h, except in loanwords, or distorted speech, or dialects. However, uncommon exceptions exist for stylistic reasons: For example, the Japanese name of the Pokémon species Cramorant is , pronounced .
The sokuon is also used at the end of a sentence, to indicate a glottal stop (IPA , a sharp or cut-off articulation), which may indicate angry or surprised speech. This pronunciation is also used for exceptions mentioned before (e.g., a sokuon before a vowel kana). There is no standard way of romanizing the sokuon that is at the end of a sentence. In English writing, this is often rendered as an em dash. Other conventions are to render it as t or as an apostrophe.
In the International Phonetic Alphabet, the sokuon is transcribed with either a colon-like length mark or a doubled consonant:
The sokuon represents a mora, thus for example the word consists of only two syllables, but four morae: ni-p-po-n.
Major Japanese dictionaries list , as a synonym for . This suggests an origin in Middle Chinese phonology, where sokusei (), also known as , referred to a checked tone, or a syllable that ends in an unreleased plosive (see ). ä¿Âè² contrasts with (literally "leisurely voice") which is a syllable that ends in a vowel, semivowel, or nasal (see ).
The Meiji-era linguist used the terms sokuon ("plosive") and hatsuon ("nasal") to describe ending consonants in Chinese (which he called , an outdated term used from the Edo period until after World War II). These sounds were classified as , and . Sokuon, in particular, were classified as follows: is the , is the , and is the . Another of à Âshima's descriptions even more explicitly related the terms sokuon and hatsuon to the four tones of Middle Chinese.
Modern Japanese sokuon arose, in no small part, from consonant assimilation that occurred when an Early Middle Japanese approximation of a Chinese sokuon, such as pu (labial), t(i) (lingual) or ki/ku (guttural), was followed by an obstruent (plosive or fricative).
In addition to Japanese, sokuon is used in Okinawan katakana orthographies to represent glottal or ejective consonants. Ainu katakana uses a small both for a final t-sound and to represent a sokuon (there is no ambiguity however, as gemination is allophonic with syllable-final t). As with tsu, sokuonâÂÂs katatana form can be used as an emoticon due to its similar appearance to the smile emoticon.
There are several methods of entering the sokuon using a computer or word-processor, such as <code>xtu</code>, <code>ltu</code>, <code>ltsu</code>, etc. Some systems, such as Kotoeri for macOS and the Microsoft IME, generate a sokuon if an applicable consonant letter is typed twice; for example <code>tta</code> generates .