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In Australian linguistics, the peripheral consonants are a natural class encompassing consonants articulated at the extremes of the mouth: labials (lip) and velars (soft palate). That is, they are the non-coronal consonants (palatal, dental, alveolar, and postalveolar). In Australian languages, these consonants pattern together both phonotactically and acoustically. In Arabic and Maltese philology, the moon letters transcribe non-coronal consonants, but they do not form a natural class.
Australian languages typically favour peripheral consonants word- and syllable-initially, and they are not allowed or common word- and syllable-finally, unlike the apicals.
In the extinct Martuthunira, the peripheral stops /p/ and /k/ shared similar allophony. Whereas the other stops could be voiced between vowels or following a nasal, the peripherals were usually voiceless.