@cite{hayes-wilson-2008}: A Maximum Entropy Model of Phonotactics #
@cite{hayes-wilson-2008}
@cite{hayes-wilson-2008} propose that phonotactic well-formedness is
probability: a MaxEnt grammar assigns each surface form a score
h(x) = Σ wⱼ · Cⱼ(x), and well-formedness is P(x) = exp(−h(x)) / Z.
Hayes & Wilson's "score" is the negation of harmonyScore:
h(x) = −harmonyScore(x), so P(x) ∝ exp(harmonyScore(x)).
Higher harmony = higher probability = better well-formedness.
This is exactly softmax(harmonyScoreR, 1) on a finite candidate set.
Key contribution: ganging #
The central empirical prediction distinguishing MaxEnt from OT is
ganging: two individually weak constraints can jointly override
a stronger one. This is impossible with OT's strict ranking, which
corresponds to exponentially separated weights (OTLimit.lean).
The Ganging definition and anti-ganging theorems live in OTLimit.lean
alongside ExponentiallySeparated, since they are two sides of the same
coin.
English onset data #
We encode a subset of the learned grammar (Table (4)) and verify that
the model assigns higher harmony (= higher MaxEnt probability via
exp_lt_exp) to attested onsets than to unattested ones (§2).
An English onset: a list of consonants preceding the nucleus.
Instances For
Constraint #1 from Table (4): *[+sonorant, +dorsal]. Weight 5.64.
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Constraint #4 from Table (4): *[ ][+continuant]. Weight 5.17.
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Instances For
Constraint #5 from Table (4): *[ ][+voice, −sonorant]. Weight 5.37.
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Instances For
Constraint #6 from Table (4): *[+sonorant][ ]. Weight 6.66.
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Instances For
The subset grammar: 4 constraints from Table (4).
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Instances For
Attested onset [k]: harmony = 0 (no violations).
Unattested onset *[ŋ]: harmony = −5.64 (violates *[+son,+dors]).
Unattested onset *[rk]: harmony = −6.66 (violates *[+son][ ]).
Attested [k] has higher harmony than unattested *[ŋ].
Attested [br] has higher harmony than unattested *[rk].
MaxEnt probability ordering: higher harmony ⟹ higher
exp(harmonyScore) ⟹ higher MaxEnt probability.
Applies exp_lt_exp (Mathlib) to harmonyScoreR (HarmonicGrammar.Basic).
Gradient well-formedness: among unattested forms, *[ŋ]
has higher MaxEnt probability than *[rk]. Uses exp_lt_exp.