Clusivity systems — typology of inclusive/exclusive distinctions

@cite{cysouw-2009}

System-level typology of how a language encodes the inclusive/exclusive distinction in 1pl pronouns. Per-referent person categories (s1, minIncl, augIncl, excl, ...) live in Features/Person.lean::Category; this file classifies systems by which of those categories they grammatically distinguish.

The substrate cut is intentionally finer than WALS Ch 39 (which collapses plain inclExcl with minimal-augmented into a single "inclusive/exclusive" value). The minimal-augmented type — which licenses a 1-dual-inclusive form in addition to a 1pl-inclusive — is the typologically distinctive property of Tagalog (kata / tayo), several other Philippine languages, and many Australian languages.

Scope: pronominal clusivity (independent personal pronouns). Verbal clusivity (WALS Ch 40, Typology.Pronouns.InclusiveExclusiveVerbal) is a separately-marked phenomenon that may dissociate from pronominal clusivity (e.g. some Athabaskan languages). The five-value enum here is a first-cut typology; @cite{cysouw-2009} discusses additional minor types (degenerate-minimal-augmented, composite-unit-augmented) that this substrate does not currently distinguish.

inductive Features.Clusivity.System : Type

Cysouw 2009 typology of pronominal clusivity systems.

The cuts: (a) is incl/excl distinguished at all? (b) is the inclusive itself further split into minimal vs augmented?

• noClusivity : System

  No clusivity distinction; 1pl is one category (English we, German wir, Standard Mandarin wǒmen).

• inclExcl : System

  Plain incl/excl: separate 1pl forms for 1+2(+3) vs 1+3 (Indonesian kita/kami, Tok Pisin yumi/mipela, Mandarin colloquial zánmen/wǒmen).

• minimalAugmented : System

  Minimal-augmented: inclusive further splits into minimal (1+2 only, surfaces as a 1-dual-inclusive form) vs augmented (1+2+others); the exclusive remains a single category. Tagalog kata/tayo/kami (per @cite{schachter-otanes-1972} Chart 7), many Australian languages.

• unitAugmented : System

  Unit-augmented: minimal-augmented plus a separate 1+2+1 form ("we two and one other"); rare (e.g. Rembarrnga).

• numberIndifferent : System

  No grammatical number distinction in pronouns at all (Pirahã ti 'I/we'); the clusivity question is moot.

@[implicit_reducible]

instance Features.Clusivity.instDecidableEqSystem : DecidableEq System

Equations

• Features.Clusivity.instDecidableEqSystem x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

@[implicit_reducible]

instance Features.Clusivity.instReprSystem : Repr System

Equations

• Features.Clusivity.instReprSystem = { reprPrec := Features.Clusivity.instReprSystem.repr }

def Features.Clusivity.instReprSystem.repr : System → ℕ → Std.Format

Equations

• One or more equations did not get rendered due to their size.

def Features.Clusivity.System.distinguishedCategories : System → List Person.Category

The 1st-person Features.Person.Category distinctions a system grammatically encodes. Captures Cysouw 2009's typology operationally: .noClusivity collapses 1+2 and 1+3 into a single 1pl (modeled here by listing only .augIncl, since .augIncl is the closest catch-all for collapsed first-person plural); .inclExcl distinguishes them; .minimalAugmented and .unitAugmented further split inclusive into minimal (.minIncl) vs augmented (.augIncl). .numberIndifferent languages have no plural form, so only .s1.

Equations

• Features.Clusivity.System.noClusivity.distinguishedCategories = [Features.Person.Category.augIncl]
• Features.Clusivity.System.inclExcl.distinguishedCategories = [Features.Person.Category.augIncl, Features.Person.Category.excl]
• Features.Clusivity.System.minimalAugmented.distinguishedCategories = [Features.Person.Category.minIncl, Features.Person.Category.augIncl, Features.Person.Category.excl]
• Features.Clusivity.System.unitAugmented.distinguishedCategories = [Features.Person.Category.minIncl, Features.Person.Category.augIncl, Features.Person.Category.excl]
• Features.Clusivity.System.numberIndifferent.distinguishedCategories = []

def Features.Clusivity.System.hasInclExcl (s : System) : Bool

A system grammatically distinguishes inclusive from exclusive iff its first-person inventory contains an exclusive category. Derived from distinguishedCategories (was a stipulated pattern-match before the 0.230.544 audit).

Equations

• s.hasInclExcl = s.distinguishedCategories.contains Features.Person.Category.excl

def Features.Clusivity.System.hasMinimalAugmented (s : System) : Bool

A system distinguishes minimal-inclusive from augmented-inclusive iff its first-person inventory contains the minimal-inclusive category.

Equations

• s.hasMinimalAugmented = s.distinguishedCategories.contains Features.Person.Category.minIncl