DRAFT 5/9/06 The role of distinctiveness constraints in phonology Edward Flemming
[email protected] 1. Introduction Distinctiveness constraints favour maximization of the perceptual differences between contrasting sounds. Perceptually indistinct contrasts are disfavored because they increase the likelihood of confusion on the part of listeners. Distinctiveness constraints are required to account for the preference for more distinct contrasts that can be observed in the typology of segment inventories (Flemming 2004). For example, there is a cross-linguistic preference for front unrounded and back rounded vowels because these yield more distinct contrasts in second formant frequency than front rounded or back unrounded vowels. Distinctiveness constraints also give rise to positional neutralization effects where a contrast is neutralized in environments where it would not be sufficiently distinct. For example, stop voicing contrasts are neutralized in final position where crucial Voice Onset Time cues are not available (Steriade 1997). However, if distinctiveness constraints interacted freely with other phonological constraints, we would expect to find other effects that are in fact unattested. For example, articulatory markedness constraints could motivate significant contextual variation in inventories of contrasts to maximize the number and distinctiveness of contrasts in the face of context-specific restrictions. Attested contextual variation in inventories is generally limited to neutralization and allophonic variation. We would also expect to find 'contextual enhancement' as a counterpart to contextual neutralization: enhancement of contrasts precisely where they would otherwise be neutralized due to insufficient distinctiveness. This phenomenon is not attested in a general form. These limitations can be understood as indicating that distinctiveness of contrasts is not the only requirement imposed by speech perception, it is also desirable for the system of contrasts to be as consistent as possible across contexts.