Chapter 117Abilitative easkay / eaykap (Ability and Possibility)

117.1 The abilitative set and its position in the TAM system

Hokkaido Ainu encodes ability and inability through a set of transitive verbs that grammaticalize as auxiliaries. Nakagawa's 表75 inventories eight such forms under the label 他動詞の助動詞的用法 'transitive verbs used auxiliarially' Nakagawa (2024: 314–319); Bugaeva places the same set in her third TAM frame beside the true auxiliaries (a, nankor) and the pair verbs (kor an, wa an), distinguished by the property that person affixes fall on the main verb rather than on the ability predicate Bugaeva (2012: 494). The full architecture of these three frames is set out in Chapter 108 (Tense, Aspect, Mood, and Modality: Overview).

The two highest-frequency members, easkay ‘be able to’ and eaykap ‘be unable to’, together rank among the most frequent modal forms in the corpus (easkay 1,447 tokens, rank 137; eaykap 1,237 tokens, rank 158) ‹corpus-confirmed›. The experiential pair amkir and eramiskari share the same constructional frame and the same lexical-negation pattern; their interaction with the negation system is developed in Chapter 128 (Negative Predicates of Ability and Cognition).

117.2 The V(ka)Vt frame: morphology and the person locus

All eight members of the set share the transitive-verb-auxiliary frame: the main predicate V carries the person affixes, and the ability auxiliary Vt follows it person-unmarked. This distinguishes the construction from the pair-verb frame (kor an, wa an), where both the main verb and the existential carry person affixes, and aligns it with the basic auxiliaries (a, nankor, easirki), which are also person-unmarked Nakagawa (2024: 314); Bugaeva (2012: 494) ‹consensus›.

The particle ka ‘even, also’ may intervene between the main verb and the ability auxiliary. This insertion is a feature of the entire transitive-verb-auxiliary class and is blocked for the basic auxiliaries Nakagawa (2024: 314). Under inability, ka functions as a scalar amplifier — adding a sense of 'not even' — and is especially frequent before eaykap in subordinate and causal clauses.

The morphological shape of easkay and eaykap reflects the e- applicative prefix: the roots askay ‘be able’ and aykap ‘be unable’ also occur without this prefix as intransitive predicates with the same meanings Nakagawa (2024: 315). In the auxiliary function the e- is part of the lexical form rather than a live derivational operation, and person affixes go exclusively on the main verb.

One additional feature separates this class from other auxiliaries: the preceding verb root can be incorporated directly into easkay, producing a compound to which the person suffix then attaches as a unit:

The compound sinotca-easkay behaves as a single verb stem for person-affix attachment; the periphrastic sequence would place the affix on the main verb sinotca alone Nakagawa (2024: 314–315).

117.3 easkay: ability and possibility

easkay ‘be able to, can’ covers general ability — whether rooted in acquired skill, physical capacity, or favourable circumstance — and possibility. It combines with intransitive and transitive main verbs without distinction Nakagawa (2024: 315). In the example below the main verb is intransitive and the scalar ka 'even' intervenes:

With a transitive main verb the person affixes reflect the standard agent–object alignment of that verb, and easkay remains unmarked:

Both examples confirm that the ability construction is a full finite clause: it takes the same nominalization apparatus as any other predicate, and the ability auxiliary occupies the slot above the main predicate, not a bound morphological position within it.

117.4 eaykap and koyaykus: inability distinguished by source

eaykap ‘be unable to, cannot’ is the dedicated negative counterpart of easkay. The relationship is lexical: inability is encoded in eaykap as a separate form, and negating easkay with somo does not produce the same value Nakagawa (2024: 315); Ijäs (2023) ‹consensus›. eaykap is semantically neutral as to whether the source of inability lies in the agent (lack of skill, physical incapacity) or in external circumstance. The scalar ka 'even' frequently precedes it in subordinate clauses:

Because ka occupies the slot between the main verb and eaykap, the standard clausal negator somo can negate the main verb without scoping over the ability predicate. The following example denies the main verb action, leaving eaykap outside the scope of somo and producing a double-negative reading:

The scope pattern is the same as for clause-internal negation before ruwe ne (see Chapter 121 (ruwe ne — the Inferential / Visual-Trace Evidential)): the negator targets the inner predicate, and the outer modal or evidential element keeps its position above it. The standard clausal negation system provides the full treatment of somo scope.

koyaykus narrows the source of inability to the situational dimension: it applies when the agent is in principle capable but a circumstance prevents the action, rather than when the agent simply lacks skill or capacity Nakagawa (2024: 316). The contrast with eaykap is one of reason rather than degree. Ijäs illustrates the distinction in a constructed example Ijäs (2023):

The morphological structure of koyaykus — comprising the ko- applicative prefix, the reflexive yay-, and a root kus — is internally visible, but the sources consulted do not derive the circumstantial-obstacle semantics compositionally from this decomposition Nakagawa (2024: 316) ‹speculative›.

117.5 Lexical negation and the negation-ability interface

The ability predicates in this set do not combine with the standard clausal negator somo ‘not’. Ability and inability are lexicalized in separate words rather than derived by negating a single base, and the same holds for the experiential pair amkir / eramiskari Nakagawa (2024: 314–316); Ijäs (2023) ‹consensus›. The pattern of suppletive ability lexemes — a positive predicate paired with a dedicated negative rather than a negated positive — is typologically widespread and consistent with the tendency for high-frequency ability expressions to lexicalize negation directly (Bybee et al. 1994).

A community observation (nukopoli, aynu-corpora Discord, 2024-11-25) adds that the ability periphrases, including easkay and its set, serve in the contexts where languages with infinitives would use a bare infinitival complement; nominalization by pe, hi, or kuni substitutes when a nominal form is required, fitting the general head-marking profile of Ainu in which the verb always carries person aynu-corpora Discord (2023–2026) ‹contested›.

The relationship between the transitive-auxiliary pair easkay / eaykap and their intransitive roots askay / aykap parallels the e- applicative derivational pattern, but the auxiliary function is grammaticalized and the e- is no longer a live derivation in this context Nakagawa (2024: 315) ‹speculative›.

The full treatment of lexical negation in ability and cognition predicates — including the experiential pair and the role of ka strengthening (ka eramiskari) — belongs to Chapter 128 (Negative Predicates of Ability and Cognition). The deontic-necessity forms (easirki, kuni, yak pirka) are treated in Chapter 118 (Deontic Necessity and Obligation (kuni ne, kus ne)), and the epistemic and intentive auxiliaries (nankor, kusu ne, rusuy) in Chapter 119 (Epistemic Modality, Dubitative, Intentive, and Irrealis).