The phonology of Japanese features about 15 consonant phonemes, the cross-linguistically typical five-vowel system of /a, e, i, o, u/, and a relatively simple phonotactic distribution of phonemes allowing few consonant clusters. It is traditionally described as having a mora as the unit of timing, with each mora taking up about the same length of time, so that the disyllabic [ɲip.poɴ] ("Japan") may be analyzed as /niQpoN/ and dissected into four moras, /ni/, /Q/, /po/, and /N/. Unless otherwise noted, the following describes the standard variety of Japanese based on the Tokyo dialect.