The basic morpheme order of Basque auxiliaries is traditionally described as following the template in (9) (Cheng & Demirdache 1993; Laka 1993; Albizu 1997; 2002; Arregi & Nevins 2012).4 This template has no formal status in the analysis to follow, but rather is used here as a descriptive tool, intended to represent the fact that these morphemes, when present, must appear in the order given. The brackets marking elements in first position are intended to represent the fact that this position may be filled either by an absolutive clitic, or, when no absolutive clitic is available, an expletive morpheme (Albizu 2002; Arregi & Nevins 2012). These facts are spelled out in section four.

Allocutive morphemes may occupy one of two slots in the template in (9)—either to the right of the ergative number morpheme, as in (10), or to the left of the ergative person morpheme, as in (11) and (12).

Importantly, in 2PL ergative contexts like (13), the ergative person morpheme appears to the left of the ergative number morpheme. Assuming unique merged positions for the allocutive and ergative morphemes in (10)–(13), then the morpheme orders in (10)–(12) seem to require movement of either the allocutive morpheme, the ergative number morpheme or the ergative person morpheme. (The only ergative person/number combination in which both person and number are overt is 2PL, with which allocutive clitics do not co-occur.)

Indeed, there is another set of contexts, called “ergative displacement” constructions in the Basque literature, in which morphemes marking ergative person may move independently of the ergative number marker -(t)e- as illustrated in (14). In ergative displacement, the leftmost slot in the auxiliary may, under conditions to be described later, be occupied by ergative person morphemes rather than an absolutive morpheme. In (14), the ergative person allomorph zen- appears in first position, while the ergative plural marker, -(t)e-, appears in its usual position, further to the right in the auxiliary.

While ergative displacement appears in all Basque dialects, dialects with allocutive displacement are much more restricted.5 In the general case, then, parsimony favors an analysis by which the position of the allocutive morpheme in (10)–(12) is invariant, and the position of the ergative person morphemes in (11) and (12) suggests an additional context in which these morphemes may undergo displacement. A partially unified analysis of these two ergative morpheme displacement contexts will be presented later.

An additional challenge posed by the morpheme order of allocutive clitics concerns the fact that they always appears to the left of the auxiliary-final -(e)n morpheme traditionally taken to be a tense marker (Laka 1993).

A well-described property of Basque auxiliaries is that they exhibit a Mirror Principle effect (Baker 1985), whereby the canonical linear order of morphemes is the inverse of their (bottom-up) merged order, on standard assumptions about argument structure and the functional sequence (Laka 1993). From the perspective of Speas & Tenny’s (2003) proposal, where morphemes marking non-thematic addressees are merged in a C-field position, and if, indeed, the -(e)n morpheme truly corresponds to a T head, then the ordering of the allocutive morpheme to the left of –en is surprising in that it suggests a merged position below T. An account of these facts is developed below.

Basque is traditionally described as having a have/be alternation (Ortiz de Urbina 1989; Arregi 2004). In unaccusative contexts without allocutive morphology, the auxiliary takes a form of the copular verb izan, ‘be’, and in transitive non-allocutive contexts takes a form of possessive ‘have’, edun, as illustrated in (16) and (17). In (16), the auxiliary root vowel is -a-, marking izan, ‘be’, while in (17), the auxiliary root vowel is -u-, marking edun, ‘have’.

The foregoing description holds for contexts without allocutive clitics. In unaccusative contexts with allocutive clitics, however, the root vowel -u- appears, as shown in (2), repeated here (Rebuschi 1981; 1984; Oyharçabal 1993; Albizu 2002; Arregi 2004; Arregi & Nevins 2012; Torrego 2013; Torrego & Fernández 2016).6

The allocutive clitics in (18) are reminiscent of ergative clitics both in their exponence (see (4)), and in the fact that they co-occur with auxiliary switch. Nevertheless, as Albizu (2002) notes, allocutive clitics in intransitive contexts are unlike thematic ergative clitics in that, in most dialects, the allocutive clitic does not undergo ergative displacement, as in (19). Thematic 2SG familiar ergative clitics, do, however as in (20) (Laka 1993; Béjar & Rezac 2009; Arregi & Nevins 2012; Torrego & Fernández 2016).

Plausibly related to the above set of facts is an additional root vowel alternation triggered in monotransitive contexts. We saw previously that monotransitive contexts without an allocutive clitic determine ‘have’, i.e. with an auxiliary root vowel -u-, as in (17). In the presence of an allocutive clitic, however, the root vowel in monotransitive contexts is not -u- but rather -i-, as in (21).

The -i- morpheme in contexts like (21) has traditionally been taken to be related to the -i- that appears in the root in ditransitive applicatives like (22) (Rebuschi 1981; 1984). These facts, alongside the fact that exponence of allocutive forms is similar to that of thematic dative forms (see (5)) suggest the possibility that allocutive clitics may be related to dative clitics.

The nature of -i- in these contexts will be addressed shortly. For the moment, let us observe that allocutive clitics differ from recipient dative clitics in several ways. First, as noted above, allocutive clitics appear to the right of ergative plural morphemes in third person ergative contexts, while clitics marking thematic datives appear to the left, as illustrated in (23).

In addition, in allocutive clitic contexts, the morpheme marking absolutive plural is -it-, as in (24). In the case of thematic dative clitics, this morpheme is standardly -izk- as in (25) (Albizu 2002).7

Finally, as Albizu (1997) notes, allocutive clitics, unlike recipient dative clitics, do not trigger Person Case Constraint (PCC) effects. In the presence of a recipient dative, agreement with a first or second person direct object is blocked:

Importantly, allocutive clitics do not give rise to PCC effects. (27) shows that allocutive clitics freely combine with an agreement morpheme marking a first person direct object—here n-.

To summarize, allocutive clitics are superficially similar to ergative and dative clitics in their exponence and in the ways they condition exponence of the ‘have’ root vowel -u- and the -i- morpheme of dative contexts. Albizu’s (1997; 2002) observations, however, suggest that allocutive clitics must be analyzed as partially distinct from “true” ergatives and recipient datives at least at certain derivational levels.

A third property of allocutive clitics to be accounted for is their effect on the exponence of a morpheme appearing on the left edge of the finite verb. As noted briefly in section 3.1, the first position slot may be occupied by one of two kinds of elements. One possible denizen of this position are first and second person clitics, generally absolutive clitics. (We return to the special case of ergative clitics in this position later.)

In third person absolutive contexts, such as (29), this slot is occupied by one of five forms—{d-, z-, l-, b-, ∅}, whose selection is determined by a complex set of factors including tense and mood.

In the Basque literature, there are two main approaches to these facts. One approach, by Lafon (1943: 379) and Ortiz de Urbina (1989), is that this latter set of forms—{d-, z-, l-, b-, ∅}—are third person absolutive markers with allomorphs conditioned by tense, mood etc. A second approach, which has been the consensus in recent literature, is that third person absolutive markers—like third person ergative—are ∅ or absent entirely (Trask 1977; 1981; Laka 1993; Albizu & Eguren 2000; Fernández & Albizu 2000; Albizu 2002; Arregi & Nevins 2012). On this approach, {d-, z-, l-, b-, ∅} are typically treated as expletive elements to fill a phonologically empty position (Laka 1993; Gómez & Sainz 1995; Arregi & Nevins 2012). Section four develops an account of these morphemes close in spirit to this latter group of proposals.

The contexts determining selection among these expletive form—{d-, z-, l-, b-, ∅}—are often said to form a natural class of tense and modality (Lafon 1943; Trask 1981; Laka 1993). In realis contexts, the morpheme surfaces as d- in present tense contexts and z- in past contexts. (30)–(32) show that this alternation is constant across unaccusative, monotransitive and ditransitive contexts (the relevance of which will be made clear shortly).8

In irrealis contexts, the expletive morpheme appears as l- in present tense contexts and z- in the standard dialect as in (33). (For convenience, only monotransitive forms are shown here.)

The importance of these facts for our analysis of allocutive morphemes relates to a fact less commonly discussed in the formal literature on allocutives, namely that exponence of the expletive morpheme is conditioned not just by tense and modality, but also by the presence of an allocutive clitic (Rebuschi 1984; Albizu 2002). This pattern, described first by Rebuschi (1984: 621) as far as I am aware, is as in (34).

Rebuschi’s generalization describes the behavior of expletives in three kinds of contexts. The first is in ditransitive constructions. In section 3.2, it was noted that in intransitive and monotransitive contexts, the presence of an allocutive clitic triggers the appearance of the root vowels -u- and -i- respectively. In present tense contexts, the expletive morpheme is unchanged—d-. This is illustrated in (35) and (36).

In ditransitive contexts with analytic verbs, the root vowel is -i- in non-allocutive contexts, and no further root-vowel change operation is applicable. Here, the addition of an allocutive clitic has no effect on the auxiliary root, but rather changes the auxiliary-initial expletive morpheme from d- to z-. (Our discussion will henceforth follow the convention in the Basque literature of referring to the d-to-z- change as “spirantization”.)10

A second context in which spirantization applies in present tense allocutive forms is with synthetic verbs—the closed class of verbs on which tense and agreement are marked on the verb rather than a separate auxiliary. In such contexts, no auxiliary is present and hence, no auxiliary root vowel change is applicable. As shown in (38) and (39), in the presence of an allocutive clitic, no change in the root applies, and the expletive morpheme is z- as in past tense contexts.

A third context described by Rebuschi’s generalization involves the transitive possibility modal auxiliary root *ezan (transitive) as in (40). Here, again, no change to the root is applicable and spirantization applies.11

As (Rebuschi 1984: 621) notes, an additional context in which no root change applies are dative intransitive contexts like (41). Rebuschi (1984: 621) suggests that in such cases, spirantization applies vacuously since there is no initial d- for the change to affect. These facts are considered below.

A question that arises at this point is what the relation is between the aux-initial z- triggered by allocutive clitics in Rebuschi’s generalization contexts, and the homophonous element triggered in past tense contexts. One possibility is that the homophony is accidental, i.e. that z- spells out different sets of features in the two contexts. A disadvantage to this solution, however, is that, in many dialects, the presence of an allocutive morpheme co-occurs with another phenomenon found in past tense forms. Examples (38) and (39), show that with synthetic verbs like etorri, ‘come’ and ibili, ‘walk’, the presence of an allocutive clitic triggers both spirantization and a change in the “buffer vowel” between the verb root and expletive morpheme (Albizu 2002).12 Whatever the nature of this buffer vowel alternation, which will not be considered in detail here, a parsimonious approach to these two alternations—spirantization and -a- → -e- buffer vowel change—will require us to assume that the homophony is not accidental and that a more general property is responsible for both of these alternations. An analysis of these facts is developed in the next section.

In recent work, Miyagawa (2012; 2017) analyzes Basque allocutive morphemes as the reflex of an Agree relation between an allocutive probe and a silent Hearer morpheme, merged in the specifier of higher speech act-related projection, S(peech)A(ct)P. Based on a structure initially proposed by Haegeman & Hill (2013), Miyagawa likens the structure in which speech act participants are introduced to a high applicative structure, in which the speaker is parallel to the agent, the addressee to the applied recipient and CP to the theme. The allocutive probe is merged on C and, after raising to the SA head c-commanding the Hearer morpheme, probes and agrees with the latter. This proposal is illustrated in (42).

From the perspective of Miyagawa’s proposal, allocutive morphemes in Basque might be thought of as a species of “vocative agreement”. That is, given the presence of vocative case in natural language, and from the perspective of approaches to case and agreement as different morphological manifestations of an Agree operation, one imagines that vocative agreement might also be overtly manifested in human language. Such an approach may turn out to be correct for other allocutive languages, but it is not well suited to modeling the Basque facts introduced above for reasons to be made clear shortly. (See Portner et al., to appear, for such an approach to a class of honorific morphemes in Korean.)

Miyagawa’s model is within a tradition of work analyzing the person morphemes on Basque verb forms as the reflex of an agree operation (Etxepare 2006; Rezac 2008; Béjar & Rezac 2009). A competing approach to these morphemes, to be adopted in the analysis to follow, is that they are instead obligatory clitics, doubling a possibly silent argument (Laka 1993; Oyharçabal 1993; Preminger 2009; Arregi & Nevins 2012). The main advantage of a clitic analysis of person morphemes has to do with the absence of Head Movement Constraint (HMC) violations. Let us assume, more or less standardly, the structure in (43) showing the merged positions of Basque ergative, dative and absolutive arguments and the three sources of case for thematic arguments.

As discussed in section 3, morphemes marking ergative, absolutive and dative arguments appear on the auxiliary verb. On an approach that takes these morphemes to reflect exponence of Agree+feature valuation, the morphemes corresponding to dative person and absolutive person will presumably be the probes Appl and v, which, after probing, will raise via head movement to the position of the auxiliary. Importantly, modals and aspectual morphemes do not appear adjoined to the auxilary. Modals are free morphemes that, in affirmative declarative sentences like (44), appear between the main verb and the auxiliary. Aspectual markers appear affixed to the main verb, as in (44), repeated here.

Assuming the structure in (43), for the absolutive and dative morphemes to raise to the position of the auxiliary, in T or higher, they will need to skip over the intervening modal and aspectual heads in apparent violation of the HMC. If, on the other hand, dative and absolutive morphemes on the auxiliary raise as clitic XPs, then the absence of HMC effects is expected.

The evidence from morpheme ordering just presented supports a clitic approach to absolutive and dative person morphemes, specifically. In the analysis to follow, allocutive morphemes will also be treated as clitics, in view of the similar behavior of these two classes of forms in terms of exponence and conditions on allomorphy, as discussed in section 2. Specifically, let us assume that clitics are elements of category D, merged in a “KP” structure with the arguments they double, as in (46) (Nevins 2011).

Following Matushansky (2006), let us assume that clitics raise as XPs to the spec of their hosts and then undergo m-merger–post-syntactic adjunction to their host heads–as in (47).

Let us assume, further, that clitics “tuck in” (Halle & Marantz 1994). That is, for a given clitic host X, m-merger will adjoin the clitic below the node formed by adjunction of the head of X’s sister, as in (48).

Let us further assume the sequence of heads in (49), which, along with their associated clitics, will form auxiliaries through successive head adjunction, with adjuncts uniformly linearized to the left of their hosts. Here, Fin is the merged position of complementizers. Following Bianchi (2003), we take Fin to be the locus of several speech act-deictic properties including speech act time and participants. The Speaker and Addressee heads will be the positions in which morphemes encoding speaker and addressee speech act roles are introduced. This structure, then, is akin to Speas and Tenny’s and Miyagawa’s sequence of speech act-related heads described above, but no position is taken here on whether this configuration should be understood as parallel to the thematic structure in which agents, themes and recipients/applied objects are introduced. In addition, unlike in Miyagawa’s analysis, these heads will be merged below the position of the complementizer, Fin, for reasons to be made clear shortly.14

In addition, following Laka (1993), Arregi & Nevins (2012) and Gómez & Sainz (1995), the foregoing discussion has assumed that, in the absence of a suitable person clitic, the first position slot is filled with an expletive morpheme. Let us assume that this reflects an EPP property of Fin, akin to standard approaches to V2 (Chomsky 2000; Roberts 2004; Holmberg 2015; Leu 2015). Let us state this requirement as in (50) for the time being. In particular, (50) will be applicable in third person absolutive contexts, where there are no third person clitics to occupy the first position slot (Arregi & Nevins 2012).

A question that arises is whether (50) applies before or after m-merger in the phonological component. The fact that absolutive first and second person clitics can satisfy (50), as in (28) (repeated here, as (51)), thereby blocking expletive insertion, suggests that either (50) applies before m-merger or that absolutive clitics do not undergo m-merger in this context. A consequence of these assumptions is that the “first position” slot—spec, FinP—will necessarily be filled by either an absolutive morpheme or an expletive element.

We saw previously that allocutive clitics appear to the left of the auxiliary-final -(e)n morpheme traditionally taken to be a tense marker in T, as shown in (15), repeated here (Laka 1993). Again, if allocutive morphemes are merged in a high Addressee position, then the order of -(e)n to the right of the allocutive clitic is surprising given that auxiliary morphemes otherwise mirror their merged orders quite consistently (Laka 1993). Let us instead follow Arregi & Nevins (2012) in taking auxiliary-final -(e)n to be not an element in T, but a past tense complementizer, in Fin. As Arregi & Nevins (2012) note, this proposal is supported by the fact that past tense -(e)n and aux-final declarative complementizers are in complementary distribution. Let us assume, further, that the presence of a past tense feature on Fin also determines spell out of the z- expletive morpheme in spec, Fin.

Basque clitics only appear in finite contexts—never in non-finite embeddings. Let us follow Arregi & Nevins (2012) in taking his property to reflect a requirement that they be licensed by adjunction to Fin, which will be discussed in greater detail shortly. The fact that absolutive clitics appear only in first position suggests that Fin is their landing site. Ergative clitics will arrive in Fin by first adjoining to T—their source of case—and subsequently to Fin through successive head adjunction. Following Laka (1993), let us assume that dative clitics target a modal head, silent in some contexts but overt as -ke in possibility modal contexts like (53). Dative clitics canonically appear left-adjacent to this head, labeled Mod, here. The proposed landing sites of person clitics are summarized in (54).

Let us now consider how these assumptions fare in modeling morpheme order in relevant contexts. (56) illustrates the proposed structure for the auxiliary in (55), with a 3PL.ERG clitic. The structure represents the application of successive cyclic adjunction of the heads in (54), and adjunction of clitics to their respective landing sites. Again, adjoined heads are uniformly linearized to the left of their hosts, and clitics “tuck in”, forming the adjunction node closest to their hosts. The arrow in (56) denotes the final head-adjunction step in the sequence.

Recall from Section 3.1 that first person ergative clitics appear unexpectedly to the right of allocutive clitics as in (11), repeated here. Exploiting further the neo-performative assumption of designated positions for Speaker and Addressee speech act roles, let us assume that contexts with first person ergative clitics differ minimally from the representation in (56) in that the ergative clitic raises to Speaker. If this involves cyclic movement of the clitic (stopping off in T), then m-merger must be allowed to fail to apply, such that the ergative clitic can raise from Spec, T. (58) shows the proposed structure for the auxiliary in (57) with a first person ergative clitic. It represents a sequence of movement steps identical to those in (56), with difference that the ergative clitic -gu has raised to Speaker.

A question raised immediately by this approach is whether clitics cross-referencing second person thematic arguments raise to Addressee parallel to the way that first person ergative clitics target Speaker. More generally, the proposal that person morphemes move to designated Speaker and Addressee projections leads to the expectation that the person hierarchy in Basque should map to linear order, at least for the relative order of first and second person morphemes (for which Basque unambiguously has person clitics).

In the standard dialect, first and second person dative morphemes do not undergo further displacement to Speaker/Addressee. That is, in terms of present proposal, they always appear adjoined to the Aux-internal Mod head. Evidence that first position dative clitics do not raise to Speaker comes from modal contexts like (59), with the verb ezan, where all dative clitics, regardless of person, appear to the left of the modal particle, -ke, as in (59), rather than to the right, where they would appear if they had raised to Speaker. Dative clitics, therefore, cannot be used to examine person effects on morpheme placement.

In addition, absolutive clitics, regardless of person, must occupy the first position slot—what has been taken here to be spec, Fin. The surface position of absolutive clitics, like dative clitics, is therefore insensitive to person hierarchy effects and cannot be used to infer evidence of movement of first and second person morphemes to Speaker and Addressee respectively. The only person clitics left, therefore, that are suitable for inferring movement to Speaker/Addressee are ergative clitics, and the only head that intervenes overtly between the position of the third person clitic and the first person clitic, to distinguish these two positions on the surface, are allocutive morphemes, as discussed above. There is therefore no way to test whether thematic second person ergative clitics raise from T to Addressee, since this movement will necessarily be string vacuous.16

A question unaddressed so far is why ergative but not dative clitics are able to raise to Addressee. One possibility is that the difference between these two classes of morphemes has to do with the nature of the way dative and ergative arguments receive case. Let us follow the consensus in the Basque literature in taking dative case in Basque to be inherent (Oyharçabal 1992; Rezac 2008). Ergative case in Basque, however, appears to be structural, assigned by T (Ortiz de Urbina 1989; Artiagoitia 2001; Rezac et al. 2014). Suppose, further, that T inherits its person features from Speaker/Addressee in the spirit of Chomsky (2008). From this perspective, one possible understanding of the movement of first person ergative clitics to Speaker is that, in such contexts, Speaker withholds its person feature, and probes the first person ergative clitic directly. (See Legate, 2011, for a likeminded proposal.) The fact that dative and absolutive clitics, which are not probed by “T-C”, do not raise to Speaker/Addressee is accounted for under this approach.

We saw previously that, in unaccusative contexts, the presence of an allocutive clitic triggers a change in the auxiliary root, -a- → -u-.

The fact that ‘have’ may appear in intransitive contexts suggests that the have/be alternation is not conditioned directly by argument structure (Arregi 2004; Arregi & Nevins 2012). Rather, the distribution of Basque have/be is reminiscent of person-sensitive have/be systems in some Romance varieties (D’Alessandro & Roberts 2010). For Basque, the Obligatory Case Parameter (Bobaljik 1993; Laka 1993) provides a useful way of implementing this idea. For ergative languages, this holds (in updated parlance) that if one source of structural case is needed, this will be the lower probe “v”. If a second source of structural case is needed, this will be the higher probe “T”. In allocutive clitic contexts, this means that T will be the source of case for the allocutive clitic. On this approach, T will have to probe the allocutive clitic after raising to the Addressee projection.

This recalls D’Alessandro and Roberts’ (2010) analysis of Abbruzzese where ‘have’ appears only where T agrees exhaustively with a goal. For Basque, the distribution of have/be might therefore be characterized initially as follows. (A modified version of this proposal is developed in the following discussion.)

Something more is needed to account for the fact that allocutive clitics trigger the root vowel -i- in transitive contexts.

Recall that -i-roots are also triggered in applicative constructions in the absence of an allocutive clitic.

This suggests that Addressee is a species of applicative head capable of supplying an extra source of case when needed (Miyagawa 2012; Haegeman & Hill 2013). Unfortunately, for our purposes, it won’t do to say that -i- spells out an applicative head directly (pace Elordieta 2001; Fernández 2015b; and Fernández 2015a), for two reasons. The first concerns a morpheme order problem: if Addressee could spell out as -i-, this morpheme should show up to the right of the allocutive and PL.ERG morphemes rather than to the left, contrary to fact. Second, as noted by Arregi & Nevins (2012), for (non-allocutive) applicative contexts like (64), if the -i- element spells out an applicative head merged TP-internally, and if Basque auxiliaries are assembled via head-movement, then, a movement step adjoining the -i-morpheme to auxiliary seems inexorably to require a Head Movement Constraint violation (Travis 1984). In particular, (65) and (66) show that both modals and aspectual morphemes linearly intervene between the auxiliary containing the -i- element and the verbal shell. (For the moment, the -i- element is agnostically glossed as DAT.)

These facts, then, suggest that -i- does not spell out an applicative head directly, but instead is determined by a vocabulary insertion rule similar to that proposed in (62), inserting -i- only in the presence of case-assigning T and Applicative heads. In other words, extending Arregi’s (2004) and Arregi and Nevins’ (2012) approach to Basque have/be, a plausible approach to -i- roots is that exponence of auxiliary roots is conditioned by phi-agreement more generally (D’Alessandro & Roberts 2010). Let us state the rule for -i- as in (67) for the time being:

Still to be explained is the relationship between the allocutive clitic and spirantization of the expletive morpheme. Recall Rebuschi’s generalization, repeated here.

The contexts where spirantization (z-) is triggered in the presence of an allocutive clitic are those where no root vowel change is possible, i.e. no form exists. A plausible understanding of these facts from the perspective of our proposal is that probing of the allocutive clitic by T* or Addressee/Applicative* is lexically blocked in these contexts, that is, there is no vocabulary item mapping to this feature set. Let us assume that in these cases, the allocutive morpheme is instead probed by Fin itself (cf. Rizzi 1997; Carstens 2003; Chomsky 2008; Haegeman & van Koppen 2012). That is, Fin is a source of case for the allocutive clitic only when other (lower) sources of case are not available, in the spirit of the Obligatory Case Parameter. Importantly, unlike the Addressee head, Fin is not applicative-like in the sense that it does not introduce an extra argument/participant.

Let us recall, now, that the other context in which expletive z- appears—past tense forms with the past tense specified complementizer -(e)n—also presumably involves probing by Fin, which must agree in its tense value with T, the locus of tense.18 This agreement is illustrated in (69). In present tense contexts, the past tense specified Fin head, -(e)n is not merged and no agreement between Fin and T applies.19

From this perspective, what the two contexts determining expletive z-—past tense forms and Rebuschi’s generalization contexts—have in common, apart from the appearance of expletive z-, is that Fin is a probe. In past tense contexts, it will agree with the past tense value on T and in allocutive contexts it agrees with the allocutive clitic.20 The distribution of expletive {d-,z-} can now be summarized as in (70).21

To summarize, the proposal developed so far models three effects of allocutive morphemes on auxiliary morphology: (i) their effect on ergative clitic placement; (ii) their effect on auxiliary roots; and (iii) their effects on first-position expletives in Rebuschi’s generalization contexts. Central to this approach is the proposal that allocutive morphemes like other person morphemes on the auxiliary are clitics that participate in phi-agreement. Moreover, the distribution of allocutive forms is similar to that of thematic addressees, and modelable using assumptions standardly employed in analyzing case and cliticization for thematic arguments in Basque. A remaining challenge for the analysis, however, concerns the exceptional behavior of dative intransitive auxiliary forms to be addressed in the next subsection.

A problematic set of facts for the analysis developed so far concerns dative intransitive constructions such as (71).

In particular, the auxiliaries in (71) pose two problems. One relates to the fact that the allocutive clitic in (71b) triggers no change in the form of the auxiliary root. Specifically, the addition of the allocutive clitic in (71b) should require agreement with T*—the next source of case available following the Obligatory Case Parameter, and this, together with Appl*, as required given the presence of the dative clitic, should trigger a spell out of the auxiliary root as -i- pursuant to (67). A second problem concerns the fact that the auxiliary root is the leftmost element in the auxiliary in apparent violation of (50). Let us consider these two issues in turn.

The consensus in the Basque historical literature is that auxiliary forms like (71b) reflect a combination of the izan root -a- with an incorporated dative marker or “dative flag” -(k)i-, which precedes the dative (Lafon 1943; Trask 1981; Hualde 2003). Palatalization of an initial d- before a high front vowel also marking dative contexts yielded the initial z- attested in the standard and most central and eastern dialects, and [x]/[j] in western dialects. This proposal is illustrated in (72).22

In addition, -ki- appears in a broader set of dialects, including the standard, in dative contexts with synthetic verbs, as in (73).

Let us assume that the -i- element in (71) is the same element as -ki- in (73). Specifically, the analysis to follow will draw on Trask’s (1981) and Fernandez’s (2015a) proposal that -(k)i- is a preposition that introduces some dative arguments and incorporates into the auxiliary.23 The idea that the -i- element in contexts like (71) represents a dative-introducing head low in the functional sequence—either a P or Appl head—has been proposed by several authors (Trask 1981; Elordieta 2001; Fernández 2015b; a noted by Arregi and Nevins (2012), an important obstacle to such an analysis of this -(k)i- as a low P/Appl head concerns morpheme order. If this applicative morpheme is merged in a position below the auxiliary, then, on this approach, this element will need to head raise across intervening aspectual and modal morphemes in apparent violation of the Head Movement Constraint (Travis 1984). (See discussion of (65) and (66) above.) Second, if—as assumed in all syntactic approaches to Basque auxiliary formation—auxiliaries are formed by successive head-adjunction, it is hard to understand why such an applicative morpheme should surface to the right rather than to the left of the (higher) auxiliary root -a- in dative intransitive contexts like (72).

The fact that -(k)i- is able to raise past intervening heads suggests that it raises as a clitic, like the person morphemes described above. Let us assume, in particular, that -(k)i- reflects the presence of a PP-doubling clitic, akin to French/Italian -y/-ci (Kayne 1975; 2008), that raises and adjoins to the auxiliary. This movement step will be independent of the step that raises the dative clitic, which will move to its host, ModP, in the usual way. Specifically, let us assume that -(k)i- undergoes m-merger and head-adjunction in the way described above for other clitics, to a position here labeled F, just above the auxiliary root, as in (74). This latter assumption is required in order to express the fact that -(k)i- surfaces to the right of the auxiliary root, (t)za-.

The distribution of the auxiliary root (t)za-, like that of its competitors -a-, -u- and -i- can now be stated in terms of the different phi-probes on the auxiliary. Specifically, (t)za- is inserted in the presence of case-assigning P* and v* heads. When an allocutive clitic is present in dative intransitive contexts (like (71b)), the allocutive clitic will be probed by T* in the usual way, i.e. with the total inventory of phi-probes {v*, P* T*}. The root will spell out as (t)za- rather than -u-, as desired, since the former is the more specific context.24 The rules governing the spellout of auxiliary heads can now be summarized in their final form in (75).

A second problem posed by dative intransitive constructions concerns the fact that the auxiliary root appears word-initially in present tense third person contexts, in apparent violation of the expletive insertion rule in (50). Let us assume, following Hualde’s (2003) suggestion, that expletive d- is inserted as usual and subsequently deleted in phonology. Such a phonological process might be related to the fact that, in Basque there are no *[dts] or *[ds] strings—the sequence that would otherwise be produced by combining expletive d- with the -(t)za auxiliary root. As a reviewer notes, however, such an approach does not explain why insertion of a buffer vowel that seems to appear in past tense forms like (76a) does not bleed this d-deletion rule, yielding the unattested (76b).25

From the perspective of Rebuschi’s generalization, a question that arises now is why the presence of an allocutive clitic triggers no expletive z-, given that no change applies to the auxiliary root. That is, what blocks the unattested form in (77c)?

On the approach developed in the previous section, expletive z- is triggered in allocutive clitic contexts when Fin probes the allocutive clitic. In contexts like (41), however, the above analysis has assumed that the extra source of case for the allocutive clitic is T, as provided for by the Obligatory Case Parameter. The absence of an expletive z- element here, as in (77c), is therefore accounted for on this approach without further assumptions.