In the International Phonetic Alphabet, is used to represent the voiceless bilabial plosive. It commonly represents the unaspirated voiceless bilabial plosive , like the pronunciation of in "spin". In Ancient Greek, beta represented the voiced bilabial plosive . It commonly represents the voiced bilabial plosive , like the English pronunciation of in "ball". Mangbetu and Ninde have phonemically voiceless bilabial trills. Coptologists believe that Coptic was articulated as a voiced bilabial fricative . Among the labial consonants, is labiodental and the rest is bilabial. The bilabial and alveolar geminates are generally longer than velar ones. In most languages which use the Latin alphabet, has a voiced bilabial or labiodental sound. The Spanish bilabial and dental approximants are commonly written as lowered fricatives, and respectively. Sonorants in such a sequence (except bilabial consonants) mostly became palatalized. There are five click articulations&colon; bilabial, dental, lateral, alveolar, and palatal. Absent stop is an areal feature (see also Voiceless bilabial stop). For instance, represents the voiceless bilabial stop, and represents the aspirated bilabial stop. In some other languages, it is used to represent other bilabial consonants.