Hiatus resolution and linguistic diversity in Australian English.

Vowel hiatus is typically resolved in Australian English through complementary strategies of liaison (j-gliding/w-gliding/linking-r) and glottalisation. Previous work suggests a change in progress towards increased use of glottalisation as an optimal hiatus-breaker, which creates syntagmatic contrast between adjacent vowels, particularly when the right-edge vowel is strong (i.e. at the foot boundary). Liaison continues to be used when right-edge vowels are weak, but glottalisation as a hiatus resolution strategy in general appears to be increasing and may be more common in speakers from non-English speaking backgrounds raising the question of whether exposure to linguistic diversity could be driving the change. We examine hiatus resolution in speakers from neighbourhoods that vary according to levels of language diversity. We elicited gliding and linking-r hiatus contexts to determine how prosodic strength of flanking vowels and speakers' exposure to linguistic diversity affect hiatus resolution. Results confirm that glottalisation occurs most frequently with strong right-edge vowels, and gliding/linking-r are more likely with weak right-edge vowels. However, strategies differ between gliding and linking-r contexts, suggesting differing implementation mechanisms. In addition, speakers from ethnolinguistically diverse areas produce increased glottalisation in all contexts supporting the idea that change to the hiatus resolution system may be driven by language contact.

Evaluating automatic creaky voice detection methods.

There is growing interest in research on the non-modal voice quality, creaky voice; however, its identification often relies on time-consuming manual annotation, leading to a recent focus on automatic creak detection methods. Various automatic methods have been proposed, which rely on varying types and combinations of acoustic cues for creak detection. In this paper, we compare the performance of three automatic tools, the AntiMode method, the Creak Detector algorithm, and the Roughness algorithm, against manual annotation of creak using data from 80 Australian English speakers. We explore the possibility that tools used in combination may yield more accurate creak detection than individual tools used alone. Based on method comparisons, we present options for researchers, including an "out-of-the-box" approach, which supports combining automatic tools, and propose additional steps to further improve creak detection. We found restricting analysis to sonorant segments significantly improves automatic creak detection, and tools performed consistently better on female speech than male speech. Findings support previous work showing detection may be optimised by performing a creak probability threshold sweep on a subset of data prior to applying the Creak Detector algorithm on new datasets. Results provide promising solutions for advancing efficient large-scale research on creaky voice.

Effects of Glottalisation, Preceding Vowel Duration, and Coda Closure Duration on the Perception of Coda Stop Voicing.

English has multiple potential acoustic cues to coda stop voicing, including the duration of the preceding vowel, the coda closure duration, and, in some varieties, glottalisation. Glottalisation associated with coda stops appears to be a recent change to Australian English (AusE) with younger speakers using glottalisation more than older speakers in production. Here we report on a study designed to examine AusE-speaking listeners' perception of cues to coda stop voicing. Listeners were presented with audio stimuli in which preceding vowel duration, coda closure duration, and the relative proportions of the rhyme that these occupy were manipulated and co-varied with the presence or absence of glottalisation. The results show that listeners used preceding vowel duration to cue coda stop voicing, and that coda closure duration was a weaker cue to voicing when not varied in conjunction with preceding vowel duration. In addition, glottalisation facilitated increased perception of coda voicelessness, even when paired with very long preceding vowels, which otherwise signal coda voicing. Although age-related differences in production have previously been reported, we found that both older and younger listeners used glottalisation similarly in perception. These results may provide support for a sound change led by a shift in perception.

Glottalisation, coda voicing, and phrase position in Australian English.

Glottalisation is an important cue to coda stop voicelessness, particularly for younger Australian English speakers who utilise glottalisation more than older speakers, suggesting a recent sound change. However, most previous studies of glottalisation in this variety of English have focussed on single word utterances, raising questions about whether glottalisation in those studies may have been prosodically conditioned rather than specific to the coda stop: Could the observed effect have been due to phrase-final creaky voice, which is acoustically similar to coda-related glottalisation? This study therefore explored the differential effects of phrase position on the production of glottalisation. Phrase-medially (where phrase-final creaky voice is not expected to occur), results confirmed previous findings that glottalisation cues coda stop voicelessness and that it does so more frequently for younger compared to older speakers. In phrase-final position, rates of glottalisation increased, but older speakers appeared more similar to younger speakers in use of glottalisation, suggesting that the change towards the increased use of glottalisation may be nearing completion in this prosodic position. Younger speakers appear to represent a more advanced stage of the change extending the use of glottalisation from phrase-final to phrase-medial position.