Colon (letter)
The colon alphabetic letter ꞉ is used in a number of languages and phonetic transcription systems, for vowel length in Americanist Phonetic Notation, for the vowels ⟨a꞉⟩ [ɛ] and ⟨o꞉⟩ [ɔ] in a number of languages of Papua New Guinea, and for grammatical tone in several languages of Africa. It resembles but differs from the colon punctuation mark, :.