Theory 19/Speech & Phonetic Science
Vowel Spaces Balance Two Costs
The claim
The size of a language's vowel space is set by the ratio of articulatory effort to perceptual distinctiveness, so languages with similar inventories can distribute vowels differently.
01The mechanism
Vowels must be far enough apart to be distinguished and close enough together to be easy to produce. The optimum spacing depends on how much the speakers value each cost.
That makes the ratio the determinant, and predicts that inventory size alone will mispredict the shape of the space.
02What this is not
Inventory-size models
Those predict vowel space from the number of vowels. This predicts its shape from the cost ratio.
03Predictions
- P1Space shape should track the ratio.
- P2Inventories of equal size should distribute differently.
04Refutation
Space shape tracking inventory size would favour the size model.