Coronal harmony in Kinyarwanda causes alveolar fricatives to become postalveolar preceding a postalveolar fricative within a stem. Alveolar and postalveolar stops, affricates and palatals block coronal harmony, but the flap and non-coronal consonants are reported to be transparent. Kinematic data on consonant production in Kinyarwanda were collected using electromagnetic articulography. The mean angle for the line defined by receivers placed on the tongue tip and blade was calculated over the consonant intervals. Mean angle reliably distinguished alveolar and postalveolar fricatives, with alveolars showing a lower tip relative to blade. Mean angle during transparent non-coronal consonants showed a higher tip relative to blade than in contexts without harmony, and the mean angle during transparent [m] was not significantly different than during postalveolar fricatives. This is consistent with a model where Kinyarwanda coronal harmony extends a continuous tip-blade gesture, causing it to be present during 'transparent' segments, but without perceptible effect.

Optimality Theory explains typological markedness implications by proposing that all speakers possess universal constraints penalizing marked structure, irrespective of the evidence provided by their language (Prince & Smolensky, 1993/2004). An account of phonological perception sketched here entails that markedness constraints reveal their presence by inducing perceptual 'repairs' to structures ungrammatical in the hearer's language. As onset clusters of falling sonority are typologically marked relative to those of rising sonority (Greenberg, 1978), we examine English speakers' perception of nasal-initial clusters-lacking in English. We find greater accuracy for rising-sonority clusters, evidencing knowledge of markedness constraints favoring such onset clusters. The misperception of sonority falls cannot be accounted for by stimulus artifacts (the materials are perceived accurately by speakers of Russian-a language allowing nasal-initial clusters) nor by phonetic failure (English speakers misperceive falls even with printed materials) nor by putative relations of such onsets to the statistics of the English lexicon.

Phonological grammars characterize distinctions between relatively well-formed (unmarked) and relatively ill-formed (marked) phonological structures. We review evidence that markedness influences speech error probabilities. Specifically, although errors result in both unmarked as well as marked structures, there is a markedness asymmetry: errors are more likely to produce unmarked outcomes. We show that stochastic disruption to the computational mechanisms realizing a Harmonic Grammar (HG) can account for the broad empirical patterns of speech errors. We demonstrate that our proposal can account for the general markedness asymmetry. We also develop methods for linking particular HG proposals to speech error distributions, and illustrate these methods using a simple HG and a set of initial consonant errors in English.