Fifty years of change to prevocalic definite article allomorphy in Australian English

The English definite article has two major allomorphs: prevocalic /ðiː/ and preconsonantal /ðə/. Recent studies have shown changes to definite article allomorphy in some English varieties. Younger speakers, particularly from culturally and linguistically diverse backgrounds, often use /ðə/ prevocalically rather than /ðiː/. The prevocalic definite article (PVDA) /ðiː/ facilitates management of vowel hiatus because it supports the emergence of [j] in preventing vowel adjacency (e.g. the ash [ðiːjœʃ]). An alternative strategy for separating adjacent vowels is glottalisation or glottal stop ([ðiːʔœʃ]). Few studies have explored the relationship between the vowel in the PVDA and hiatus management during the process of change. We report a diachronic analysis of Australian English (AusE) PVDA and associated hiatus management across a 50-year period (∼1960s to ∼2010s) and a synchronic analysis of present-day speakers from mainstream (MS) and non-mainstream (non-MS) (diverse) backgrounds using two read-sentence contexts. The aim is to provide insight into the process of change and factors that may influence its progression. Speech data from adolescents recorded in 1959/1960 were compared with recordings from Mainstream AusE-speaking (MS) young people recorded in the 2010s. Results showed significantly greater incidence of schwa in the PVDA and hiatus-breaking glottalisation in the modern data, particularly amongst females. The synchronic analysis comparing present-day MS and non-MS speakers showed increased use of glottalisation in females and non-MS speakers. Additionally, acoustic analysis showed more schwa-like productions in the PVDA by non-MS speakers. Of key importance in both analyses is that glottalisation was more prevalent than schwa, possibly indicating glottalisation triggered the change.