Modelling opacity and variation in Gran Canarian Spanish apocope

In this paper, we present novel data from Spanish spoken on Gran Canaria which show an interaction of two lenition processes: final consonant deletion and vowel apocope. We show that in certain positions in an utterance, these processes optionally combine in a fed counterfeeding interaction. Furthermore, the variation present in the dialect due to process optionality uncovers a latent opacity pattern, i.e. an additional opaque interaction that is not motivated by any individual input-output mapping, but only by the quantitative aspect of variation. This takes the form of mutual counterfeeding, a rarely reported phenomenon, thus creating a novel test case for theories of opacity. The second part of the paper provides a formal analysis of the opacity-ridden data, taking into account process optionality and variation. The theoretical analysis and learning simulations using the Expectation-Driven Learner demonstrate that a probabilistic variant of Serial Markedness Reduction can capture both fed counterfeeding and latent opacity without recourse to additional mechanisms beyond the original framework, as opposed to analyses in other serial frameworks such as OT-CC. Our analysis shows that opacity with optional processes is a complex problem that has to be specifically addressed with probabilistic frameworks.