Lexicon against Naturalness: Unnatural Gradient Phonotactic Restrictions and Their Origins∗

This paper presents two cases of lexically gradient phonotactic restrictions that operate against what would be phonetically natural: Tarma Quechua and Berawan. The paper shows that the unnatural trends in the lexicon are statistically significant, phonetically real, and show clear signs of productivity, with evidence from loanword phonology and from morphophonological alternations. Based on the two cases presented, we argue that gradient phonotactics can operate in the unnatural direction: in a context where one value of a feature (in our case, [±voice]) is phonetically dispreferred across languages, that marked feature value may actually be preferred by phonotactics (e.g., voiceless rather than voiced stops after a nasal or intervocalically). To our knowledge, this is the first report of a (truly) unnatural gradient phonotactic restriction on segmental structure. The unnatural gradient phonotactics in Tarma Quechua and Berawan bear theoretical implications: we demonstrate that Harmonic Grammar with Con restricted to natural constraints disallows phonotactic restrictions that favor the unnatural feature value in a given environment, contrary to what is attested in our data. Based on Author 1, the paper also proposes a new historical explanation for the development of these unnatural patterns. We argue that each of them is the result of a special sequence of three phonetically natural sound changes — a so-called “blurring chain”. This hypothesis explains several peculiar aspects of the data, derives the typology of natural/unnatural processes, and provides a new historical explanation for unnatural patterns in general.