Chapter 118Deontic Necessity and Obligation (kuni ne, kus ne)

118.1 The deontic field

Hokkaido Ainu expresses necessity and obligation periphrastically. There is no bound deontic affix; instead, three distinct constructions carry the semantic load. The auxiliary easirki ‘must, have to’ expresses strong obligation. The auxiliary kuni ‘should, be supposed to’ — the same element that heads purpose-complement clauses — expresses normative expectation or scheduled necessity; combined with the copula ne it forms the predicate kuni ne, the principal deontic proposition form. A set of conditional predicates — yak pirka, yak wen, yakka pirka, yakka wen — provides a gradient from advice to permission to futility Nakagawa (2024: 309–310, 423–424); Bugaeva (2012: 493–494). The prospective kus(u) ne, treated fully in Chapter 119 (Epistemic Modality, Dubitative, Intentive, and Irrealis), acquires a near-command reading with a second-person subject and the final particle na Nakagawa (2024: 423).

All of these forms occupy the pre-evidential slot in the clause. The scope ordering that Chapter 108 (Tense, Aspect, Mood, and Modality: Overview) establishes — kusu ne ruwe ne (grammatical) vs *ruwe ne kusu ne (ill-formed) — holds for deontic modals equally: deontic meaning is expressed inside the evidential predicate Nakagawa (2024: 393). The imperative and the prohibitive, which express directive force through the bare-stem form and the preverbal adverb iteki, are treated in Chapter 114 (Imperative and Prohibitive (Directive Mood)).

118.2 easirki — obligation

easirki ‘must, be obliged to’ is listed in Nakagawa's table of core Saru auxiliaries (本来的な助動詞) alongside nankor, kuni, and rusuy Nakagawa (2024: 306–309, 表74). Like other core auxiliaries it carries no person index of its own; only the preceding main verb is inflected. Bugaeva glosses it as "deontic mood (must)" and places it in the modal paradigm alongside nankor (probability) and rusuy (desiderative) Bugaeva (2012: 493). The strength of the obligation it expresses — "must, cannot avoid" — places it at the stronger end of the deontic scale, above the advisory yak pirka.

The auxiliary is invariant; no plural or evidential inflection attaches to it. Its position is immediately after the main verb, with no conjunctive particle between them — the frame shared by nankor, rusuy, and nisa. The frequency of easirki in the Hokkaido corpus is substantially lower than that of nankor (approximately 2402 tokens) ‹corpus-suggested›, consistent with the stronger deontic commitment it expresses and its restriction to contexts of genuine obligation.

118.3 kuni ne — normative expectation

kuni appears in Nakagawa's 表74 as a core auxiliary with the semantic range "〜はずだ / べきだ / ことになっている": it should be the case that / one ought to / it is scheduled or expected that Nakagawa (2024: 310). The same element is the irrealis complementizer that heads purpose complements and the object complements of desiderative and manipulation predicates. The deontic auxiliary reading arises when kuni is predicated with the copula ne in a main clause — V kuni ne — such that the nominalized proposition 'that V' is presented as a normative expectation. The grammaticalization path runs from kuni as a formal noun nominalizing an irrealis proposition, through its complementizer use, to the main-clause modal reading; the complementizer and purpose functions are the primary locus of kuni, and the deontic reading is the most grammaticalized end of that scale ‹speculative›.

In the Saru corpus kuni appears most often in complement position before cognition verbs such as ramu 'think'. The aynu-corpora Discord records this distribution: kuni a=ramu is the standard structure for reported intention, with kuni nominalizing the embedded clause before the cognition verb, rather than the unattested sekor a=ramu aynu-corpora Discord (2023–2026) (nukopoli, aynu-corpora Discord, 2024-11-09) ‹corpus-confirmed›.

When kuni ne closes a main clause with no embedding cognition or purpose verb, the reading shifts to normative expectation: 'it is the normative case that V', which in context yields obligation or convention. This is semantically adjacent to easirki at the stronger end and to yak pirka at the weaker end, but kuni ne specifically encodes that the situation is normatively ordained — by role, rule, or convention — rather than urgently commanded Nakagawa (2024: 310).

Interaction with the evidential layer follows the standard scope ordering: the deontic predicate sits inside the evidential, so kuni ne ruwe ne (obligation as established fact) is well formed and *ruwe ne kuni ne is not Nakagawa (2024: 393). Negation goes inside the deontic operator: somo V kuni ne expresses the normative expectation that one does not V. Ainu has no infinitive; the nominalization-plus-copula strategy that yields kuni ne is the same architecture that covers what infinitives do in European languages — a point the aynu-corpora Discord makes explicitly for the kuni nominalizer family aynu-corpora Discord (2023–2026) (nukopoli, aynu-corpora Discord, 2024-11-25) ‹consensus›.

118.4 The yak pirka idioms: advice, prohibition, permission, and futility

A set of clause-final predicates is built on the conditional particles yak 'if' and yakka 'even if' followed by the evaluative adjectives pirka ‘be good’ or wen ‘be bad’. These four expressions cover advice, negative advice, permission, and futility Nakagawa (2024: 423–424); Ijäs (2023). Nakagawa groups them among indirect and mitigated command forms because they are typically directed at a second-person addressee and carry the second-person subject prefix — unlike the bare imperative, which has no subject prefix. The illocutionary force follows from the evaluation: 'if you V, [the situation] is good' yields advice or permission; 'if you V, [the situation] is bad' yields negative advice or futility depending on whether the conditional is simple (yak) or concessive (yakka) Nakagawa (2024: 423) ‹consensus›.

Permission via yakka pirka is negated with somo inside the conditional to express 'you need not V' rather than 'you must not V'; the latter is expressed by yak wen or, for a direct prohibition, by iteki V Nakagawa (2024: 424). The yak and yakka particles are the same ones that govern conditional and concessive adverbial clauses; their grammar is set out in Chapter 135 (Conditional, Temporal, and Concessive Clauses).

118.5 kus(u) ne na as near-command

The prospective auxiliary kus(u) ne — analysed in Chapter 119 (Epistemic Modality, Dubitative, Intentive, and Irrealis) as the conjunction kusu plus the copula ne expressing intention or scheduled future Nakagawa (2024: 435); Satō (2008: 85–86) — acquires a directive reading when the subject is second person and the final particle na closes the clause. In that context e=arpa kus ne na 'you will go, then' functions as a softened instruction Nakagawa (2024: 423). The same indirect-command function is available with nankor na and p ne na Nakagawa (2024: 423). Ijäs presents the same range for kus(u) ne — 'be going to, intend to, plan to' — and the analysis adopted here keeps the two-morpheme segmentation (conjunction kusu + copula ne) against her pedagogical one-word spelling kusune Ijäs (2023) ‹consensus›.

The construction iteki … kus ne na extends the prohibitive adverb iteki into the mitigated-prohibition frame, producing 'be careful not to V'; Nakagawa provides an attested example and Ijäs's rendering iteki e=eyruska kus ne na hani! matches it Nakagawa (2024: 425); Ijäs (2023) ‹consensus›.

118.6 Scope and the epistemic–deontic boundary

All the deontic forms treated in this chapter occupy the pre-evidential layer. Proposition-level negation goes inside the deontic operator: somo V kuni ne expresses the normative expectation that one does not V, while kuni ne itself remains outside the scope of negation. For the yak idioms, negation either enters the antecedent clause (somo V yakka pirka 'need not V') or is supplied by switching to the opposed evaluative adjective (yak wen for yak pirka) Nakagawa (2024: 423–424).

The boundary between epistemic and deontic modality is not categorical. The conjecture auxiliary nankor, whose core value is probability, takes on expectational coloring equivalent to a softened command when addressed to a second person with na Nakagawa (2024: 311). The prospective kus ne straddles intention and near-command. The forms easirki and kuni ne carry no epistemic probability component: easirki is a judgment of obligation, kuni ne is normative expectation. The full treatment of nankor and kus(u) ne as epistemic and intentive forms belongs to Chapter 119 (Epistemic Modality, Dubitative, Intentive, and Irrealis); the relation of the kuni complementizer to purpose clauses is in Chapter 107 (The kuni Complementizer and Purpose Complements) and Chapter 136 (Causal and Purpose Clauses (kusu)).