A formant study of the alveolar versus retroflex contrast in three Central Australian languages: Stop, nasal, and lateral manners of articulation.

This study presents formant transition data from 21 speakers for the apical alveolar∼retroflex contrast in three neighbouring Central Australian languages: Arrernte, Pitjantjatjara, and Warlpiri. The contrast is examined for three manners of articulation: stop, nasal, and lateral /t ∼ ʈ/ /n ∼ ɳ/, and /l ∼ ɭ/, and three vowel contexts /a i u/. As expected, results show that a lower F3 and F4 in the preceding vowel signal a retroflex consonant; and that the alveolar∼retroflex contrast is most clearly realized in the context of an /a/ vowel, and least clearly realized in the context of an /i/ vowel. Results also show that the contrast is most clearly realized for the stop manner of articulation. These results provide an acoustic basis for the greater typological rarity of retroflex nasals and laterals as compared to stops. It is suggested that possible nasalization of the preceding vowel accounts for the poorer nasal consonant results, and that articulatory constraints on lateral consonant production account for the poorer lateral consonant results. Importantly, differences are noticed between speakers, and it is suggested that literacy plays a major role in maintenance of this marginal phonemic contrast.

An acoustic study of nasal consonants in three Central Australian languages.

This study presents nasal consonant data from 21 speakers of three Central Australian languages: Arrernte, Pitjantjatjara and Warlpiri. The six nasals considered are bilabial /m/, dental /n/, alveolar /n/, retroflex /ɳ/, alveo-palatal /ɲ/, and velar /ŋ/. Nasal formant and bandwidth values are examined, as are the locations of spectral minima. Several differences are found between the bilabial /m/ and the velar /ŋ/, and also the palatal /ɲ/. The remaining coronal nasals /n n ɳ/ are not well differentiated within the nasal murmur, but their average bandwidths are lower than for the other nasal consonants. Broader spectral shape measures (Centre of Gravity and Standard Deviation) are also considered, and comparisons are made with data for stops and laterals in these languages based on the same spectral measures. It is suggested that nasals are not as easily differentiated using the various measures examined here as are stops and laterals. It is also suggested that existing models of nasal consonants do not fully account for the observed differences between the various nasal places of articulation; and that oral formants, in addition to anti-formants, contribute substantially to the output spectrum of nasal consonants.

An acoustic study of multiple lateral consonants in three Central Australian languages.

This study presents dental, alveolar, retroflex, and palatal lateral /̪ll ɭ ʎ/ data from three Central Australian languages: Arrernte, Pitjantjatjara, and Warlpiri. Formant results show that the laminal laterals (dental /̪l/ and palatal /ʎ/) have a relatively low F1, presumably due to a high jaw position for these sounds, as well as higher F4. In addition, the palatal /ʎ/ has very high F2. There is relatively little difference in F3 between the four lateral places of articulation. However, the retroflex /ɭ/ appears to have slightly lower F3 and F4 in comparison to the other lateral sounds. Importantly, spectral moment analyses suggest that centre of gravity and standard deviation (first and second spectral moments) are sufficient to characterize the four places of articulation. The retroflex has a concentration of energy at slightly lower frequencies than the alveolar, while the palatal has a concentration of energy at higher frequencies. The dental is characterized by a more even spread of energy. These various results are discussed in light of different acoustic models of lateral production, and the possibility of spectral cues to place of articulation across manners of articulation is considered.