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 (小さいつ^?) or chiisana tsu (小さなつ^?), meaning "little tsu". Compare to a full-sized tsu:

The sokuon is used for various purposes. The main use is to mark a geminate consonant, which is represented in rōmaji (romanized Japanese) by the doubling of the consonant (except when the following consonant is ch). It denotes the gemination of the initial consonant of the kana that follows it.

Examples:

The sokuon cannot appear at the beginning of a word, before a vowel kana (a, i, u, e, or o), or before kana that begin with the consonants n, m, r, w, or y (in words and loanwords that require geminating these consonants, ン, ム, ル, ウ, and イ are 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.

The sokuon is also used at the end of a sentence, to indicate a glottal stop (IPA [ʔ], a sharp or cut-off articulation), which may indicate angry or surprised speech. 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.

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