An investigation of the dynamics of vowel nasalization in Arabana using machine learning of acoustic features

This paper presents exploratory research on temporally dynamic patterns of vowel nasalization from two speakers of Arabana. To derive a dynamic measure of nasality, we use gradient tree boosting algorithms to statistically learn the mapping between acoustics and vowel nasality in a speaker-specific manner. Three primary findings emerge: (1) NVN contexts exhibit nasalization throughout the entirety of the vowel interval, and we propose that a similar co-articulatory realization previously acted to resist diachronic change in this environment; (2) anticipatory vowel nasalization is nearly as extensive as carryover vowel nasalization, which is contrary to previous claims; and (3) the degree of vowel nasalization in word-initial contexts is relatively high, even in the #_C environment, suggesting that the sound change *#Na > #a has involved the loss of the oral constriction associated with N but not the complete loss of the velum gesture

Rhotic contrasts in Arabana

Arabana has a three-way rhotic phoneme contrast: /r/ (alveolar trill) vs /ɾ/ (alveolar tap) vs /ɻ/ (retroflex continuant). The rhotic contrasts are prosodically restricted in Arabana. The triple contrast only appears following the tonic vowel, which is the first vowel. In other onset positions /ɻ/ is contrastive, but there is no /r/ vs /ɾ/ contrast. There is no contrast in coda positions. We undertook the first-ever production study of Arabana rhotics. Recorded audio materials were independently coded in PRAAT by two trained transcribers. We found the following allophony: /r/ [r, ɾ, ɹ]; /ɾ/ [ɾ, ɹ], /ɻ/ [ɻ]. The /r/ vs /ɾ/ contrast is thus negatively determined, /r/ permits [r] realizations, but /ɾ/ does not. The commonest realization of both /r/ and /ɾ/ is [ɹ]. The phoneme in neutralized coda position is /r/. The high degree of overlap in realizations between /r/ and /ɾ/ accords with reported perception difficulties

Pre-stopping in Arabana

Pre-stopping is a widespread and usually non-contrastive phenomenon in Australian languages. Contrastive pre-stopping is rare and materials on it are limited. Based partly on original phonetic data, this paper provides evidence that Arabana, a language of northern South Australia, has contrastive pre-stopping of both laterals and nasals. Current analyses of pre-stopping, both contrastive and non-contrastive, model pre-stopped sequences as complex segments, and relate their diachrony to perceptual motivations favouring the enhancement in the discrimination of place oppositions. We provide evidence that pre-stopped sequences in Arabana are best analyzed as heterosyllabic clusters, and that their diachrony centrally involves perceptual motivations favouring the augmentation of phonologically strong constituents, specifically stressed syllables.This research was supported by: (i) Language Documentation Grant CE140100041 ‘Metrical Prominence and Pre-stopping in Arabana’ from the ARC Centre of Excellence for the Dynamics of Language; (ii) ARC Discovery Project DP140100863 ‘Reconstructing Australia’s Linguistic Past: Are All Australian Languages Related to One Another?’; (iii) ARC Discovery Project DP130103935 ‘The Indigenous Grammar of Aboriginal English: Implications for Language Contact Theory’

Rhotic contrasts in Arabana

Arabana has a three-way rhotic phoneme contrast: /r/ (alveolar trill) vs /ɾ/ (alveolar tap) vs /ɻ/ (retroflex continuant). The rhotic contrasts are prosodically restricted in Arabana. The triple contrast only appears following the tonic vowel, which is the first vowel. In other onset positions /ɻ/ is contrastive, but there is no /r/ vs /ɾ/ contrast. There is no contrast in coda positions. We undertook the first-ever production study of Arabana rhotics. Recorded audio materials were independently coded in PRAAT by two trained transcribers. We found the following allophony: /r/ [r, ɾ, ɹ]; /ɾ/ [ɾ, ɹ], /ɻ/ [ɻ]. The /r/ vs /ɾ/ contrast is thus negatively determined, /r/ permits [r] realizations, but /ɾ/ does not. The commonest realization of both /r/ and /ɾ/ is [ɹ]. The phoneme in neutralized coda position is /r/. The high degree of overlap in realizations between /r/ and /ɾ/ accords with reported perception difficulties.This research was supported by ARC Discovery Projects Reconstructing Australia's linguistic past: Are all Australian languages related to one another? (DP140100863) and The Indigenous Grammar of Aboriginal English: implications for language contact theory (DP130103935)