The Role of Phonetic Naturalness in Phonological Rule Acquisition

The speed and reliability of language acquisition in human infants remain puzzling facts, especially given the huge variability in the quality and quantity of the speech input. It has been argued that such a robust learning path is due to a specialized Language Acquisition Device (Chomsky 1965), which incorporates statistical mechanisms to extract regular patterns from noisy input (e.g. Saffran, Aslin & Newport 1996), as well as innate constraints that restrict learning to patterns that conform to universal grammar (Chomsky 1981). In the domain of phonological acquisition, discussion has centered around the role of phonetic naturalness as a possible learning constraint. That is, phonological rules and patterns tend to respect a number of constraints that are grounded in phonetic factors and that might guide the language learner (Archangeli & Pulleyblank 1994; Hayes 1999). Some experimental work with infants has been carried out that examines the role of phonetic naturalness in acquisition, in particular that of surface phonological regularities (Saffran & Thiessen 2003; Seidl & Buckley 2005). In this article, we focus on the acquisition of phonological rules. We begin by illustrating the presence of naturalness constraints with rules of the type shown in (1).