Psychological reality of sequential voicing ("Rendaku") in modern standard Japanese: Its acquisition and development

The thesis is a psycholinguistic study of Sequential Voicing (known as Rendaku) in modern Japanese. Rendaku is a morphophonemic alternation whereby an initial voiceless obstruent of the second constituent of a compound undergoes voicing. It is infamous for its irregularity, which is attributed to more than a dozen conditioning factors. The study questions its status as a 'productive phonological rule' and investigates the way in which it is acquired and developed by 131 adult and non-adult native speakers. The psychological reality of Rendaku is tested orally by means of an elicited production test and by an acceptability test, both involving nonsense words as compound constituents. Two theories join forces to interpret the results. Optimality Theory provides the most up-to-date analysis of Rendaku, notably of the OCP[+voice, -son] effect (the disfavouring of adjacent voiced obstruents) that blocks the phenomenon. It also enables the construction of a model of multi-staged developmental grammars, each identified by a unique constraint ranking and its outputs. The dual-mechanism model of morphological learning, supplemented by findings on morphological representations and the acquisition of compounds, explains how regular and irregular aspects of Rendaku can be handled differently in the cognitive system. The results show: 1) late acquisition, presumably triggered by the growth in vocabulary and general cognition, 2) low productivity, indicating the weakness of the process, 3) OCP[+voice, -son] as a near-categorical constraint, 4) the distance effect of the OCP, 5) the absence of productive Rendaku for the majority of subjects, 6) psychologically real effects of some phonological conditions, 7) notable individual variations, for instance the preference of voicing certain obstruents. It is concluded that for most subjects Rendaku is not a productive rule of grammar as often described, but is largely a part of generalizations in the lexicon. Different speakers seem to construct different I-linguistic generalizations about Rendaku, which suggests the idea of "parametric poverty" - that is that certain parameters may be set randomly or left unset