Morphological Composition: Phenomena #
@cite{link-1983}
Empirical tests for the Core.Morphology pipeline, verifying that
stem-based generation produces correct surface forms and features
from real English lexical entries in Fragments/English/.
Coverage #
- Regular plurals: dog → dogs, student → students
- Irregular plurals: man → men, child → children, person → people
- Mass nouns: water, furniture — no plural paradigm
- Proper names: John, Mary — no plural paradigm
- Verb agreement: sleep → sleeps (vacuous), eat → ate (vacuous)
- Vacuity: all verb inflection is semantically vacuous
Regular plural: "dog" → "dogs"
Regular plural: "student" → "students"
Regular plural: "horse" → "horses"
Irregular plural: "man" → "men" (not *"mans")
Irregular plural: "child" → "children" (not *"childs")
Irregular plural: "woman" → "women"
Irregular plural: "person" → "people" (suppletive)
Irregular plural: "fireman" → "firemen"
Singular base features include number := some.Sing.
Plural rule sets number := some.Plur.
Count nouns have countable := some true.
Mass noun "water" has no plural paradigm.
Mass noun "furniture" has no plural paradigm.
Mass noun "rice" has no plural paradigm.
Proper name "John" has no inflectional paradigm.
Proper names get category PROPN.
Common nouns get category NOUN.
Proper names carry person := some.third.
Verb 3sg: "sleep" → "sleeps"
Verb past: "eat" → "ate"
Verb 3sg: "know" → "knows"
All verb inflectional rules are semantically vacuous (per entry).
The vacuity theorem generalizes: it holds for ANY VerbEntry.
NounEntry.toStem preserves the lemma as formSg.
Count nouns get exactly one paradigm rule (plural).
Mass nouns get zero paradigm rules.
With the mereological plural rule, plural marking is NOT semantically vacuous: there exist predicates and entities for which the plural denotation differs from the base. This witnesses @cite{link-1983}'s point that singular and plural nouns denote distinct sets.
The flat plural rule IS semantically vacuous (for toy models).
The Zwicky & Pullum CliticAffixProfile and the MorphRule framework
characterize the same morphological operations from complementary angles:
CliticAffixProfileclassifies a morpheme's distributional behavior (paradigm gaps, selection, scope idiosyncrasies)MorphRulespecifies the morpheme's compositional semantics (form rule, feature rule, semantic effect)
The bridge theorems below verify that these independent characterizations agree on whether a morphological operation carries semantic content.
The plural -s affix is classified as an inflectional affix by
Zwicky's diagnostics, AND is semantically non-vacuous in the
MorphRule framework. Both analyses agree that plural marking
carries semantic content.
The past tense -ed affix is classified as inflectional by
Zwicky's diagnostics. In the MorphRule framework, verb tense
inflection is vacuous at the word level (tense semantics is
compositional, handled by Semantics.Intensional). This is NOT
a disagreement: Zwicky's hasSemanticIdiosyncrasies tracks
compositionality failures (like "last" ≠ "most late"), while
MorphRule.isVacuous tracks whether the regular semantic
contribution is non-trivial.
All nouns in the fragment with irregular plurals produce the
correct irregular form via toStem, matching the paradigm gaps
and idiosyncrasies that Zwicky's criterion B/C predict for
inflectional affixes.
The @cite{bybee-1985} relevance hierarchy orders morpheme categories by semantic relevance to the verb stem. Categories with higher relevance rank (e.g., agreement = 8) are less semantically relevant — and therefore more likely to be semantically vacuous.
We verify that MorphRule.isVacuous is consistent with Bybee's
predictions: agreement morphology (rank 8, least relevant) is vacuous,
while number on nouns (which changes denotation via @cite{link-1983}) is not.
Verb agreement (3sg -s) has category =.agreement,
which has the highest relevance rank (= least relevant to
verb meaning). This predicts semantic vacuity — and indeed
verbAgreement3sg has isVacuous = true.
Plural noun marking has category =.number, distinct from
.agreement — it changes the noun's denotation.
The full mereological rule has isVacuous = false.
The .number and .agreement categories have different relevance
ranks, reflecting that noun number is semantically contentful while
verb agreement is vacuous.
Per-entry regularity verification: changing a verb's isRegular flag
breaks exactly one theorem.
Rule-grounding for regular verbs: stored forms match expected output.
Concrete string checks close by rfl; changing a verb's stem or form
fields breaks exactly the relevant theorem.
Batch consistency: for every regular verb, the stored forms match
the rule-computed forms. A single native_decide covers all entries.