between a vowel and a nasal, and voiceless elsewhere, such as at the beginning or end of the word or next to another obstruent. That is the case in Dravidian and Australian languages and in Korean but not in Mandarin or Polynesian. Usually, the variable sounds are transcribed with the voiceless IPA letters, but for Australian languages, the letters for voiced consonants are often used. It appears that voicelessness is not a single phenomenon in such languages. In some, such as the Polynesian languages, the vocal folds are required to actively open to allow an unimpeded (silent) airstream, which is sometimes called a breathed phonation (not to be confused with breathy voice). In others, such as many Australian languages, voicing ceases during the hold of a stop (few Australian languages have any other kind of obstruent) because airflow is insufficient to sustain it, and if the vocal folds open, that is only from passive relaxation. Thus, Polynesian stops are reported to be held for longer than Australian stops and are seldom voiced, but Australian stops are prone to having voiced variants (L&M 1996:53), and the languages are often represented as having no phonemically voiceless consonants at all. In Southeast Asia, when stops occur at the end of a word they are voiceless because the glottis is closed, not open, so they are said to be unphonated (have no phonation) by some phoneticians, who considered "breathed" voicelessness to be a phonation. Yidiny consonants, with no underlyingly voiceless consonants, are posited. References Further reading Phonation