Chapter 33The Word-Class Inventory and the Noun/Verb Bipartition

33.2.1 Verbs

A verb can function as the head of a predicate without a copula and indexes its arguments with person affixes. An intransitive verb takes one affix (the sole argument S), a transitive verb takes up to two (the transitive subject A and the object O), placed on different sides of the stem Nakagawa (2024: 116). Verbs subclassify by valency: 0-argument existential (an ‘exist’), 1-argument intransitive (arpa ‘go’), 2-argument transitive (e ‘eat’), and 3-argument ditransitive (kore ‘give’). The full taxonomy is in Chapter 36 (Verbal Subclasses: A Valence-Based Word-Class Taxonomy), the valency system in Chapter 57 (Transitivity, Valence Classes, and Ambitransitivity), and the person-affix paradigm in Chapter 62 (Architecture of the Personal-Affix System: The Four Persons and the S/A/O Paradigms).

Property-meaning words form no separate adjective class: they take the same S affix as action verbs, occur as bare predicates with no copula, and accept verbal derivational morphology. The two examples below illustrate bare property-verb predicates:

The same 1SG intransitive-subject prefix ku= that marks the action verb ku=mina 'I laugh' marks the property verb ku=pewre 'I am young' Nakagawa (2024: 118). The full argument for dissolving the adjective class is in Chapter 37 (The 'No Adjective Class' Thesis: Property Concepts as Stative Verbs).

33.2.2 Nouns

A noun heads a noun phrase serving as a verb argument, does not occupy the predicate slot on its own, and carries at most one person affix — the possessive (transitive-subject) affix, not the nominative affix of verbs Nakagawa (2024: 116, 214–216); Nakagawa (2022: 473, 480). Four subclasses differ in independence, in relativisation potential, and in the type of person affix they admit:

The table synthesises Nakagawa's 表47–48 Nakagawa (2024: 215–216). The person-affix asymmetry is the sharpest diagnostic: the affiliative form of a common noun takes the possessive (A-type) affix — ku=tekehe 'my hand' — whereas a locative noun takes the objective (O-type) affix — en=sam 'my side' Nakagawa (2024: 215–216, 241). An affix cannot appear on a bare concept-form noun: *ku=tek is ungrammatical as a possessive.

Common nouns split by possession type: alienable possession uses a kor ‘have’-construction (a=kor cip 'my boat'); inalienable possession uses the affiliative form (ku=tekehe 'my hand'); an appositive N₁ N₂(concept) construction marks attribute or scope rather than ownership (menoko tek 'a woman's hand', not replaceable by a possessive prefix) Nakagawa (2024: 217–219). These constructions are developed in Chapter 43 (The Alienable/Inalienable Split and Possessive Classification) and Chapter 44 (Concept Form vs. Affiliative (Possessed) Form).

Locative nouns (位置名詞) are a small, closed set expressing relative position ('on, beside, inside, behind'). Their basic forms require a preceding antecedent NP; their long forms can head a clause independently. Both take the objective affix and always function as place arguments, distinguishing them formally from common nouns Nakagawa (2024: 238–248). The following example shows the Type-1 locative noun sam ‘beside’ with the first-singular objective affix:

The full inventory of locative nouns, their long-form morphology, and the Type-1/Type-2 divide are in Chapter 52 (Relational and Spatial (Locative) Nouns and Their Possessed Forms).

Hokkaido Ainu nouns carry no grammatical number: the same form serves for one or many, and number marking is never obligatory Nakagawa (2024: 259); Kindaichi & Chiri (1936: 30–31). The formal noun utar ‘companions, people’ can optionally mark a plural or associative group; in the Saru dialects its range extends to inanimates on animist grounds, since all things carry a spirit in the Ainu worldview Nakagawa (2024: 259):

Community members have elaborated that utari (formally the affiliative form of utar) carries a distinct semantic range — 'family, kinship companions' — with the possessed form implying a specific relational anchor in a way the bare plural marker does not (thegodofneet, aynu-corpora Discord 2025; aynu-corpora Discord (2023–2026); corroborated by Nakagawa (2024: 251–252)) ‹contested›. Transnumerality, the animacy-scope dispute, and the interaction with verb number are in Chapter 41 (Nominal Number: Transnumerality, -utar, and the Locus of Plurality); the four noun subclasses are in Chapter 34 (Nominal Subclasses and Obligatorily-Possessed (Bound) Nouns).

33.2.3 Formal (defective) nouns

Formal nouns (形式名詞, also called 名助詞 noun-particles) cannot head an NP without a preceding modifier and supply the nominal head of a nominalised clause Nakagawa (2024: 257–258); Nakagawa (2022: 480–482). Canonical members include p ‘thing, one (after V)’/pe ‘thing, one (after C)’, hi ‘fact, time, place’, katu ‘manner, state’, kur ‘person’, uske ‘place’, and utar ‘people, companions’. The allomorphy p after a vowel / pe after a consonant is phonologically conditioned Satō (2008: 177).

Four formal nouns grammaticalise further into the evidential system: ruwe, siri, hawe, and humi are affiliative forms of the sensory nouns ru ‘track, path’, sir ‘appearance, land’, haw ‘voice’, and hum ‘sound, feeling’ that become the inferential, situational, reportative, and sensory evidentials; the full architecture is in Chapter 120 (The Nominalization-plus-Copula Evidential Schema). A productive instrument-nominalisation pattern makes the clause-head role of formal nouns visible: ani 'with' plus a transitivised verb plus p yields 'the thing for X-ing with' — ani e=kanpinuye p 'pencil' (nukopoli, aynu-corpora Discord 2026; aynu-corpora Discord (2023–2026)). The full inventory is in Chapter 35 (The Formal / Defective Noun Set (ruwe, hawe, siri, humi, hi, pe, kur)) and the nominalizing function in Chapter 101 (The Nominalizers -p/-pe and -i/-hi (Participant, Event, Place, Fact)).

33.2.4 Adverbs and postpositional adverbs

Adverbs modify verb phrases without entering the predicate slot or argument structure. They take neither the nominative person affix nor the possessive affix. Formation types include bare underived forms (ramma ‘always’, earkinne ‘very’); intransitive verbs plus the adverbialiser -no ‘-ly’ (pirkano ‘well’, tunasno ‘quickly’); and directionals built from locative-noun stems (ekimne ‘mountain-ward’, esoyne ‘to the outside’) Nakagawa (2024: 273–282). The adverbialiser and the degree/comparison system are in Chapter 61 (The Adverbializer -no and Adverb Formation from Verbs) and Chapter 146 (Adverbs, Degree Words, and Comparison Strategies).

A subclass of postpositional adverbs (後置副詞) takes an antecedent NP and functions like a postposition while remaining adverb in syntax: it can stand clause-initially and does not require its argument to be a place NP, unlike a locative case particle Nakagawa (2024: 280–282). When the antecedent is pronominal, a postpositional adverb takes the objective person affix. Canonical members include sekor ‘thus, quotative’, pak ‘until’, osi ‘after’, ani ‘with, by means of’, and tura ‘together with’ Nakagawa (2024: 280–281). Their relationship to the case system is in Chapter 53 (Postpositions, Local Case, Motion Events, Comitative, and Instrumental).

33.2.5 Adnouns and prenominals

Adnouns (連体詞, also called prenominals) modify noun phrases directly and share none of the verbal properties: they do not head predicates, do not appear as arguments, and take no person affix. The sole distributional privilege of the adnoun is that a case particle can attach to it directly, without an intervening formal noun — toan ta 'over there' joins a demonstrative prenominal with the locative particle directly, while a common noun requires a formal noun first Nakagawa (2024: 283, 288). Subclasses include demonstratives (tan ‘this’, toan ‘that’), numeric (sine ‘one’, tu ‘two’), interrogative (hemanta ‘what kind of’), indefinite, and general prenominals (pinne ‘male’, matne ‘female’, sonno ‘true, real’) Nakagawa (2024: 283). A prenominal followed by the formal noun pe ‘thing’ yields a demonstrative pronoun (tanpe ‘this thing’, toanpe ‘that thing’); the demonstrative system is in Chapter 50 (Demonstratives, Anaphora, and Definiteness).

The property verb pon ‘be small’ occupies the same pre-noun position as an adnoun but retains full verbal morphology in the predicate, illustrating the verb/noun continuum developed further below:

33.2.6 Particles and auxiliary verbs

Particles attach to autonomous clause elements and express grammatical relations without entering the predicate slot or argument structure. Nakagawa Nakagawa (2024: 295) recognises five subtypes: case particles (格助詞 — ta ‘at/in’, wa ‘from’, un ‘to’, peka ‘via’, ne ‘become (translative)’), auxiliary particles (助動詞), adverbial/focus particles (副助詞), final particles (終助詞), and conjunctive particles (接続助詞). Ainu has no nominative or accusative case particles: subject and object are identified through word order, person affixes, and context Satō (2008: 3); Nakagawa (2024: 296). The four locative case particles all require a place argument and are distinct from postpositional adverbs that can stand clause-initially Nakagawa (2024: 296, 281–282).

The Handbook chapter Nakagawa (2022: 473) splits auxiliary verbs into a seventh class on the grounds that they head predicates but cannot stand as independent words. Items such as rusuy ‘want to’ and easkay ‘be able to’ typically fuse with the preceding verb (arpa-rusuy=an 'I want to go'), while the perfective particle a ‘PFV’ never does; the boundary is gradient rather than sharp Nakagawa (2024: 291–292) ‹contested›.

33.2.7 Interjections

Interjections stand alone as complete sentences with no syntactic relation to a surrounding clause Nakagawa (2024: 290). They form a large and dialect-specific inventory of greetings (irankarapte ‘greetings’), calls, acknowledgements, and emotional expressions. The class is treated in Chapter 148 (Interjections, Response Words, Ideophones, and Sound Symbolism).

33.4.1 The verb–noun continuum

Intransitive verbs convert to nouns without morphological change: the same form is a predicate in one clause and a noun-modifier or compound-noun constituent in another, so the verb/noun boundary is positional and relational rather than marked on the word itself Nakagawa (2024: 267–272). Compound-noun formation makes this visible: Nakagawa's arity-based analysis after Kirikae (1984) shows that many items classed as N+N compounds have a verbal non-head — onture-p 'strawberry' (literally 'that which swims upstream') has a 1-argument-verb head Nakagawa (2024: 267–268). Community observation has noted that Ainu has very few coordinate or exocentric pure-noun compounds (haca-hapo 'parents', po-at 'womb'); most nominal compound formation is verb-centred, in keeping with the near-universal convertibility of intransitives to nouns (antitwilight, aynu-corpora Discord 2026; aynu-corpora Discord (2023–2026)) ‹contested›. Compound structure is in Chapter 39 (Noun–Noun Compounding: Headedness, Linking, and Semantics); nominal and verbal derivation in Chapter 60 (Denominal and Deverbal Verb Derivation).

33.4.2 Conjunctions: a distributed category

No independent conjunction class (接続詞) is set up. Items glossed as conjunctions in earlier work — akusu ‘then, when’, yakun ‘if’, oraun ‘after that’, kusu ‘because’, yakne ‘as for, if’ — are distributed between conjunctive particles and adverbs on the basis of their primary function Nakagawa (2024: 116–117); Satō (2008: 3). Even Tamura, who had set up a conjunction category, noted that it was handled as conjunctive particles for convenience Nakagawa (2024: 117). Refsing Refsing (1986: 76) keeps conjunctions, interjections, and adverbs together in one macro-class — the counterpart of the modern distributed analysis ‹contested›. The same item (oraun, kusu) receives the label conjunction, conjunctive particle, or postpositional adverb depending on the analytical framework, a terminological split with no consequence for the forms themselves. The discourse-connective system is in Chapter 147 (Conjunctions and Discourse Connectives).

33.4.3 Nominalizers: subclass or grammatical role?

The status of nominalizers is the deepest terminological split in the literature. Satō Satō (2008: 174–182) distinguishes 名詞化辞 (nominalizer) — producing an internally complete content clause — from 形式名詞 (formal noun) — the head of a relative clause with a gap; both are noun subclasses in his system. Nakagawa Nakagawa (2024: 503–504) retains 形式名詞 as the word-class label and uses 補文標識 (complementizer) for the grammatical role a formal noun plays in certain clausal contexts, so that nominalising a VP and heading a relative clause are two uses of one class, not two classes. Refsing Refsing (1986: 259–264) uses "nominalizer" more broadly to cover what Chiri treated as mood morphemes (ruwe, siri, hawe) as one of four sentence-conversion types. The three analyses are incompatible at the word-class level, though they agree on the inventory of forms involved ‹contested›.

A diachronic proposal that the affiliative suffix -i derives from the formal noun hi is Nakagawa's own and flagged as a hypothesis Nakagawa (2022: 493) ‹speculative›. Community discussion has noted that the absence of a true infinitive in Hokkaido Ainu — where head-marking and nominalisation-dependent grammar leave no role for a bare verbal noun — means that pe, hi, and kuni nominalisations with auxiliary-like predicates handle what many languages express with infinitives or purpose clauses (nukopoli, aynu-corpora Discord 2024; aynu-corpora Discord (2023–2026)) ‹contested›. The formal-noun inventory is in Chapter 35 (The Formal / Defective Noun Set (ruwe, hawe, siri, humi, hi, pe, kur)) and the nominalizing function in Chapter 101 (The Nominalizers -p/-pe and -i/-hi (Participant, Event, Place, Fact)).