Two types of voiceless nasals

Many languages in South East Asia have voiceless nasal consonants that contrast with their voiced counterparts. What has not been reported previously is that there are two distinct types of voiceless nasals. We will begin by considering the more well-known type, found in languages such as Burmese. These voiceless nasals are usually said to have an open glottis for most of the articulation, but some voicing for the period just before the stricture is broken (Ladefoged 1971: 11). In this view they have two parts. The first is necessary to distinguish them from their voiced counterparts. The second distinguishes one voiceless nasal from another, by making the place of articulation more apparent; the voiced offglide from the nasal into the vowel has formant transitions that are characteristic of each place of articulation. Dantsuji has shown that, in addition, the voiced portion of the voiceless nasals in Burmese “includes significant cues which can distinguish points of articulation” (Dantsuji 1986: 10). Despite the small voiced portion, in most phonological treatments of these sounds, a voiceless nasal consonant is considered not as a sequence of two items, a voiceless segment followed by a voiced segment, but as a single voiceless unit with a low level phonetic rule inserting the voicing towards the end. Burmese is a textbook example, with forms as shown in Table 1 (from Maddieson 1984; also in Ladefoged 1993: 282).