The sokuon (促音) 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 :n 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 (there is no ambiguity however, as gemination is allophonic with syllable-final t).