Sokuon


The sokuon is a Japanese symbol in the form of a small hiragana or katakana tsu. In less formal language it is called chiisai tsu or chiisana tsu, meaning "small tsu". It serves multiple purposes in Japanese writing.

Appearance

In both hiragana and katakana, the sokuon appears as a tsu reduced in size:
Full-sizedSokuon
Hiraganaつっ
Katakanaツッ

Use in Japanese

The main use of the sokuon is to mark a geminate consonant, which is represented in rōmaji by the doubling of the consonant. It denotes the gemination of the initial consonant of the kana that follows it.
Examples:
The sokuon usually cannot appear at the beginning of a word, before a vowel kana, or before kana that begin with the consonants n, m, r, w, or y. In addition, it does not appear before voiced consonants, or before h, except in loanwords, or distorted speech, or dialects. However, uncommon exceptions exist for stylistic reasons.
The Japanese name of the character Cramorant from the Pokémon franchise is ウッウ.
The sokuon is also used at the end of a sentence, to indicate a glottal stop, which may indicate angry or surprised speech. This pronunciation is also used for exceptions mentioned before. 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 Nippon consists of only two syllables, but four morae: ni-p-po-n.

Use in other languages

In addition to Japanese, sokuon is used in Okinawan katakana orthographies. Ainu katakana uses a small ッ both for a final t-sound and to represent a sokuon.

Computer input

There are several methods of entering the sokuon using a computer or word-processor, such as xtu, ltu, ltsu, 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 tta generates った.

Other representations