Aussie

From a clipping of Australian (or Australia) + -ie.

The spelling likely adopted the visual template of the pre‐existing personal diminutive Aussie (from Austin or Augusta). However, while the personal nickname retains standard English phonics with a voiceless /s/, the pronunciation of the national slang (/ˈɒzi/) was driven by a highly productive morphophonological template in Commonwealth slang that strongly favors short stressed vowels and lenited consonants.

The clipped base promotes the historically unstressed initial vowel to the short /ɒ/. This reflects a broader Commonwealth phonological rule where the /ɔː/ typically associated with the ⟨au⟩ digraph is shortened before a tautosyllabic /s/ or /s/‐cluster (as in austral). To lock in this short vowel on the page and prevent readers from reverting to an open‐syllable pronunciation, writers doubled the s as a structural dummy consonant.

This created an orthographic trap. The spelling effectively represents a conservative /ˈɔːsi/, preserving the standard phonetic values of both the long vowel and the voiceless fricative. However, the egalitarian colloquial register actively demanded the lenited (voiced) /z/ (compare Tassie, Brissie, possie, cossie). Thus, the dialect compromised by writing the conservative, etymological ⟨ss⟩, while speaking the colloquial /z/.

Though popularized internationally as military slang from 1915 onwards, early printed evidence shows the clipping was already active in Australian sporting vernacular by at least 1913.

1913 January 29, The Referee‎[1], Sydney, page 14:“Aussie,” as the “heads” prefer to call Australian, won by 1min 14sec from the second boat, Lilian.