Chapter 85The Reflexive-Possessive si- and the yay-/si- Division

85.1 Overview

The prefix si- ‘AUTOC/ANTIC/REFL; REFL.POSS’ has to be glossed by construction. On verbs, Bugaeva's 2025 analysis treats it as historically reflexive but synchronically chiefly autocausative (AUTOC: self-induced motion or change), with a secondary/emerging anticausative (ANTIC) use; where the object slot remains genuinely self-coreferent, as in the 'pretend to' construction with the causatives -re/-ka, the gloss stays REFL. In Nakagawa's arity calculus and in Satō's direct/indirect account, it still reduces the external argument frame by one and shifts the resulting verb to the intransitive S-index set. On nouns and incorporated nominals, however, si- is REFL.POSS: it marks the noun as belonging to the clause subject, as in si-ram 'one's own heart' Bugaeva (2025: §3.1.2); Nakagawa (2024: 188–189); Bugaeva & Kobayashi (2022: §4.2.2).

si- is more restricted in distribution than yay-: the latter attaches to transitives, intransitives, and nouns alike (with arity 0 on nouns, as in yay-kotan ‘one's own village’), whereas si- is productive only on transitive bases Nakagawa (2024: 188). Beyond the basic reflexive reading it also functions as a reflexive-possessive, marking the subject-coreferent possessor of an incorporated nominal, and it enters a 'pretend to' construction when combined with the causative suffixes -re and -ka Nakagawa (2024: 189); Satō (2007). The meaning that underlies all three uses is the same: the subject's involvement passes through another participant or external circumstance rather than arising from direct self-initiated action.

85.2 The yay-/si- division of labour

Four analyses of the yay-/si- contrast are on record, all working from the same minimal pairs. The classic pair is pusu ‘float something up’ → yay-pusu ‘pop up volitionally’ 'pop up by swimming (volitionally)' versus si-pusu ‘float up spontaneously’ 'float up of itself', attributed to Kindaichi (1931: 149, reported by Satō (2007)) and Tamura (1996: 622). Nakagawa adds rayke ‘kill’ → yay-rayke ‘commit suicide’ 'commit suicide' versus si-rayke ‘be ruined by ill fortune’ 'be ruined by ill fortune' Nakagawa (2024: 188–189).

The direct/indirect analysis (line four) is the framework Nakagawa (2024: 189) and the Handbook adopt as the current working account ‹contested›. Satō (2007: ≈31–38) builds it from three paradigm cases: si-nuye ‘have oneself tattooed’ 'have oneself tattooed' (traditional Ainu tattooing required another person to do the work); si-kasuy-re ‘have others help oneself’ 'have others help oneself' (the help comes from outside); and si-ranpewtek-ka ‘pretend not to know’ 'pretend not to know' (the pretence succeeds only if another observer believes it). In each case the subject's reflexive involvement is mediated by another party's action or perception. Satō himself qualifies the account as not yet established (定説ではない) Satō (2007).

None of the earlier analyses is fully discredited. The intentionality framing (Kindaichi, Tamura) captures the spontaneous reading of si-pusu but not the pretend-to construction, where the subject acts with full intent. The agentive/patientive framing (Kirikae 1994: 316, reported by Satō (2007)) separates the forms at the thematic role level, but feigning sleep — si-mokor-e ‘pretend to sleep’ — is agentive and falls outside the patientive characterisation. The argument-structural restriction that Kobayashi (2008: 140) derives — si- occupies Theme or Patient but never causee — correctly excludes causee arguments but does not explain the opposition between si-pusu and yay-pusu, where both occupy a Theme role Kobayashi (2010).

The Handbook extends the empirical base with two additional minimal pairs: yay-tuy-tuy-e ‘brush dust off oneself’ versus si-tuy-tuy-e ‘shake off (while becoming a bird)’ — where the latter signals a shedding of human clothes driven by the subject's transformation into bird form, an outward change not self-initiated — and yay-etaye ‘draw oneself outward’ 'draw oneself out' versus si-etaye ‘withdraw, pull back’ 'withdraw, pull back in response to another's approach' Bugaeva & Kobayashi (2022: §4.2.2).

A discussion on the aynu-corpora Discord (nukopoli, aynu-corpora Discord (2023–2026), 2024) labels the contrast as anticausative (si-) versus reflexive proper (yay-), on the grounds that si- marks 'something that happens to the subject through another force' and yay- marks 'the subject acting on itself directly'. The labelling is consistent with the Satō analysis and invokes an explicit anticausative category ‹contested›. A separate thread (aomidori_cs_, aynu-corpora Discord (2023–2026), 2023) proposed that one prefix may originally have encoded a voice distinct from reflexive proper, without adducing corroborating evidence ‹speculative›.

85.3 The reflexive-possessive function

When a transitive verb incorporates a body-part or closely possessed nominal, si- can mark that nominal as belonging to the subject — the reflexive-possessive function. The example cited by the Handbook is si-etu-uyna ‘hold one's own nose’ 'hold one's nose', where si- supplies the possessor 'one's own' for the incorporated noun etu ‘nose’ and uyna ‘hold something’ is thereby intransitivized Bugaeva & Kobayashi (2022: §4.2.2). The parallel yay--possessive yay-par-oyki ‘feed oneself; do to one's own mouth’ — 'feed oneself', literally 'do to one's own mouth' — shows that both prefixes can supply the possessor of an incorporated nominal, with the yay-/si- distinction projecting onto the possessive domain in the same way it does onto the reflexive Bugaeva & Kobayashi (2022: §4.2.2).

The reflexive-possessive reading also surfaces obligatorily in locative contexts: when a locative nominal's possessor is coreferential with the clause subject, si- (or the applicative construction built around it) is required, and substituting a non-coreferential possessor yields a distinct, non-reflexive reading Satō (2008: 251–253).

In arity terms the function remains −1: the incorporated nominal fills one argument slot, si- fills that nominal's possessor internally, and one external argument is removed. The parallel in noun incorporation is the possessor-requiring subject type, where the stranded possessor receives a reflexive interpretation by recovery from the clause subject — the 'reflexive interpretation rescue' in Satō's markedness calculus, treated in Chapter 89 (Subject Incorporation and Possessor-Stranding) Satō (2022: §3.3, §5).

The reciprocal construction uses the same word-internal possession pattern with u-. Forms such as u-tek-kisma ‘shake hands’, u-oruspe-nu ‘discuss things’, and u-itak-nu ‘agree; obey’ are treated together with the reflexive patterns in Chapter 86 (The Reciprocal u-). The shared structure is a possessor prefix followed by a bare incorporated noun and its verbal host.

85.4 The 'pretend to' construction

si- combined with a causative suffix yields a 'pretend to V' reading. Nakagawa (2024: 189) gives three examples with the productive suffix -re: si-mokor-e ‘feign sleep’ 'feign sleep', si-kamuyne-re ‘pretend to be a kamuy’ 'pretend to be a kamuy', and si-ponpene-re ‘act childishly’ 'act childishly'. With the direct-causative -ka, Satō (2007: ≈36) gives si-ranpewtek-ka ‘pretend not to know’ 'pretend not to know'. In each instance the state or appearance is externally attributed: sleep must be witnessed to be believed, kamuy status requires another to be deceived, ignorance requires an observer to accept it. The 'pretend to' reading is therefore a direct realisation of the indirect-reflexive semantics of si- in a context of social inference.

The construction is limited to verbs of state or appearance assignable by an external observer; verbs of direct physical action or creation do not enter it Nakagawa (2024: 189).

85.5 Position in the verb template

In the slot ordering summarised in Chapter 73 (Valency, Voice, and Noun Incorporation: Overview), si- precedes the root and any incorporated nominal but follows the applicative prefixes. The ordering constraint with yay- is decisive: yay-si- is attested — Nakagawa (2024: 189) cites yay-si-turi-re ‘lay oneself down while stretching’ 'lay oneself down while stretching' — while the reverse *si-yay- is not Nakagawa (2024: 189). This places si- closer to the root, in a position Nakagawa compares to forming affixes.

The derivation chain illustrates the ordering across the arity calculus: the ditransitive ko-i-ruska yields the intransitive si-ko-i-ruska when si- is prefixed — it absorbs the applicative complex's object slot while remaining to its left Nakagawa (2024: 210–211); Bugaeva & Kobayashi (2022: §4.1.1). In the polysynthetic example discussed in Chapter 73 (Valency, Voice, and Noun Incorporation: Overview) — a=e-yay-ko-tuyma-si-ram-suy-pa — a second si- sits immediately before the incorporated noun ram ‘heart’ in the reflexive-possessive reading ('one's own heart'), while yay- occupies the outer layer at the applicative boundary. The yay-outer / si-inner hierarchy is visible in a single stacked verb form Shibatani (1990: 73); Bugaeva & Kobayashi (2022: §4.1.1).