As the Dyirbal language of Australia nears extinction, its diminishing social function is accompanied by reduction within the linguistic system. If we place semi-speakers on a continuum according to the degree to which their language has been simplified, it is possible to trace changes in the grammar of the dying language. Focusing on morphological and syntactic ergativity demonstrates that decay in terminal Dyirbal involves systematic variation along the continuum. Reduction occurs on various levels, affecting syntactic operations and morphology. However, the data suggest that important formal and functional differences exist between dying Dyirbal and a typical pidgin.* This paper investigates structural change in the Dyirbal language of Australia as it approaches extinction. Radical changes have occurred in the dying language, affecting both morphological and syntactic ergativity. Such reduction in the linguistic system, however, is far from a patchwork of ad-hoc errors. The patterned nature of reduction in language death is apparent in the systematic collapse of ergative allomorphs and in the gradual weakening of the S/O pivot operation (cf. Dixon 1979). In ? 1, a sociolinguistic sketch of dying Dyirbal is provided. In ?2, 1 deal with the semi-speakers of the language. In ?3, allomorphic reduction of the ergative affix is described; in ?4, I show changes in syntactic ergativity. In ?5, I present a comparison of changes in ergative case-marking and in S/O pivot operation along the semi-speaker continuum. Finally, ?6 investigates the light that these findings shed on general linguistic debate. SOCIOLINGUISTICS 1.1. THE SETTING. Dyirbal was originally spoken over more than 8,000 square kilometers in the rain forest of north-east Queensland; some six contiguous tribes spoke what can be regarded as dialects of a single language. The population of each tribe was approximately 500. Because of the impact of European civilization (white expansion began in the 1860's), the traditional tribal unit disintegrated: territory was invaded, religious sites were desecrated, and the physical environment was deeply bruised by the impact of clearing the land for pasture and 'progress'. Some Aboriginal people were transported to * I am most grateful to R. M. W. Dixon, Nancy Dorian, and Jane Hill for helpful suggestions on this paper. I would also like to express my gratitude to George Watson and to the people of the Jambun community for their warm friendship and willingness to share their knowledge of Dyirbal with me. The following abbreviations are used in this paper: A, transitive subject; ACC, accusative; ANTIPASS, antipassive derivational affix; ASP, aspectual; DAr, dative; DU, dual; ERG, ergative; INTR, intransitive; LOC, locative; NOM, nominative; NONFUT, non-future; NP, noun phrase; 0, transitive object; PL, plural; PURP, purposive; REDUP, reduplicated; REL, relative clause marker; S, intransitive subject; TD, Traditional Dyirbal; TR, transitive; YD, Young Dyirbal. Individual speakers are also referred to by initials; e.g., LN, EM. The following orthographical differences to Dixon 1972 should be noted: j = Dixon's /l/ (lamino-palatal stop), r = // (retroflex), rr = Irl (trill), ny = /j/ (laminopalatal nasal).