Interaction between general prosodic factors and language-specific articulatory patterns underlies divergent outcomes of coronal stop reduction

Prosodically-conditioned reduction of /t/ and /d/ is examined in both English and Spanish using real-time magnetic resonance imaging. Results indicate that in both languages, the displacement of all three articulators used to create tongue tip closure (tongue tip, tongue body, and jaw) is conditioned by the duration of the movement. This suggests that reduction is a gradient rather than categorical process and argues against a rule-based allophonic account. Moreover, the results suggest that reduction in both languages arises from a similar cause. While the process is the same in the two languages, the details of the coronal constriction differ—English produces coronal stops at the alveolar ridge while Spanish produces them at the teeth. It is argued that this difference in articulatory posture underlies the divergent outcomes of coronal reduction in the two languages (flapping in English vs. spirantization in Spanish).