- A glottal stop or “choked sound”.
- The sokuon: a small form of ツ (tsu). In romanization, this is represented by doubling the following consonant. The equivalent in hiragana is っ.
- (Internet slang) Used to emphasize a letter at the end of a word.
The katakana syllabary is used primarily for transcription of foreign language words into Japanese and the writing of loan words (collectively gairaigo), as well as to represent onomatopoeias, technical and scientific terms, and the names of plants, animals, and minerals. It is also occasionally used in some words for emphasis, or to ease reading; katakana may be preferred for words becoming buried in the text if they are written under their canonical form in hiragana. Names of Japanese companies, as well as certain Japanese language words such as colloquial terms, are also sometimes written in katakana rather than the other systems. Formerly, female given names were often written in katakana. 
- (Katakana) 片仮名; アァ, イィ, ウゥヴ, エェ(𛀀), オォ, カヵガ, キギ, クㇰグ, ケヶゲ, コゴ, サザ, シㇱジ, スㇲズ, セゼ, ソゾ, タダ, チヂ, ツッヅ, テデ, トㇳド, ナ, ニ, ヌㇴ, ネ, ノ, ハㇵバパ, ヒㇶビピ, フㇷブプ, ヘㇸベペ, ホㇹボポ, マ, ミ, ムㇺ, メ, モ, ヤャ, , ユュ, エ/, ヨョ, ラㇻラ゚, リㇼリ゚, ルㇽル゚, レㇾレ゚, ロㇿロ゚, ワヮヷ, ヰ𛅤ヸ, , ヱ𛅥ヹ, ヲ𛅦ヺ, ン𛅧, ー, ヽ, ヾヿ
- (Southern Min additional) ウ̅ゥ̅, オ̅, カ̣,キ̣, ク̣, ケ̣, コ̣, サ̅サ̣̅, セ̅セ̣̅, ソ̅ソ̣̅, タ̣, チ̣, チ̅チ̣̅, ツ̣ツ̅ツ̣̅, テ̣, ト̣, パ̣, ピ̣, プ̣, ペ̣, ポ̣, , , , , , ,