Let us start by considering languages where neither phase heads nor wh-elements are specified for EF valued as Q, that is, [EF:Q] is not part of the inventory of EFs of the language. In such case, there is no featural motivation for wh-elements to undergo wh-movement as they are not themselves lexical hosts for [EF:Q] and cannot be assigned [EF:Q] by phase heads. Such languages display in situ wh-phrases regardless of whether we have single or multiple wh-questions. Chinese (see e.g. HUANG, 1982) and Japanese (see e.g. SAITO, 1985) are well-known examples of such languages, as illustrated in (23) and (24).

(23) Chinese (BOŠKOVIĆ, 2002)

John gei-le shei shemme?

John give-PERF who what

‘What did John give to who?’

(24) Japanese (SAITO, 1985)

Taroo-ga dare-ni nani-o ageta no?

Taroo-NOM who-DAT what-ACC gave Q

‘Who did Taroo give what?’

The so-called wh-phrase in this type of language is generally an indefinite that is interpreted as an interrogative constituent in the domain of an interrogative complementizer (see CHENG, 1997 for relevant discussion). From the perspective of the current system, such morphological ambiguity may reflect the lack of [EF:Q] in the language.

On the opposite side of the spectrum of typological possibilities for multiple wh-questions, we have languages where wh-phrases are obligatorily specified for a valued instance of EF ([EF:val]). In such languages, all wh-phrases must move overtly to check their EF. Let us then consider the details of the relevant derivations.

Chomsky (2008) has proposed that traces do not induce intervention effects; only a whole chain does. According to this view, Y can cross the trace of X in a configuration such as (25a) below even if they are of the same type (that is, even if they satisfy the requirements for some version of Rizzi’s (1990) Relativized Minimality to apply), but not the whole chain (X_i, t_i) (see (25b)). A problem for this proposal is that movement of Y across the trace of X in (25a) is not cyclic, violating the Extension Condition (see CHOMSKY, 1995). Crucially, if movement of Y proceeds in a cyclic fashion, X is a full (trivial) chain at the derivational step where Y should move, as sketched in (26). Sticking to the Extension Condition, Chomsky’s (2008) solution is to compute minimality violations only at the phase level, after all movement operations have taken place. Although the proposal captures the wanted contrast between (25a) and (25b), it is conceptually unattractive as it invokes a representational computation in a model that strives to enforce a derivational approach to syntactic computations.

(25)

a. [ X_i … Y_k … t_i … t_k …]

b. *[Y_k … X_i … t_i … t_k …]

(26) *[Y_k … X_i … t_k …]

However, there is a way to capture the contrast between (25a) and (25b) in a cyclic fashion, still keeping to a uniform derivational approach. The most common situation involving nontrivial chains is that a less specified element moves to a position where it becomes more specified. In (27) below, for instance, an element X with an unvalued feature moves to a position where this feature becomes valued. Suppose that the relevant distinction is not between traces and whole chains, but between being fully specified and not being fully specified. One may then naturally assume that if a given element has an unvalued feature, it can’t be properly taken into account for minimality computations. In the derivational step in (28a), for instance, Y can cross X even if they are of the same type, because X is not sufficiently specified to count as a proper intervener; in (28b), on the other hand, the relevant feature of the upper instance of X is valued and induces a minimality violation, for X has now become a fully specified element.

Figure 2

Although conceptually different, both proposals make the same predictions when we are dealing with unvalued uninterpretable features. Things change when we consider valued uninterpretable features, instead. As argued by Pesetsky and Torrego (2007), among others, the relation between interpretability and valuation is not biconditional (contra CHOMSKY, 2001) and we also find cases of valued uninterpretable features (which must still be checked against matching interpretable features in order to be licensed). In this scenario, movement of Y across X with a valued uninterpretable feature, as sketched in (29) below, should yield a minimality violation. Despite the fact that X still has to move later to check F against a matching interpretable feature F’, it is already fully specified at the derivational stage in (29).

(29) *[Y_k … X_[F:val] … t_k …]

I would like to propose that this is exactly what happens in languages where wh-elements are obligatorily specified with a valued instance of EF. The relevant value for EF associated with wh-phrases is generally Q (for question) or Foc (for focus). But regardless of the specific value, if a wh-element is specified for a valued instance of EF, it must move to a position where it can have its EF licensed. In single wh-questions, this implies that in situ wh-phrases are excluded. In the case of multiple wh-questions, the highest wh-phrase moves to check its EF against an appropriate head, as sketched in (30a-b) below with EF valued as Q for concreteness, but the other wh-phrases cannot follow suit, due to the fully specified trace left by the highest wh-phrase, as shown in (30c).

Figure 3

In other words, in languages where wh-phrases are obligatorily specified for a valued instance of EF, there is no convergent output for multiple wh­-questions. If any wh-phrase remains in situ, the presence of an unchecked instance of EF causes the derivation to crash; on the other hand, multiple wh-fronting is blocked, for a valued instance of EF on a given WH (or its trace) renders its bearer a proper intervener for the movement of the lower wh-phrases. To put this in broader terms, the system proposed here allows us to capture the generalization according to which languages that do not allow multiple wh-questions do not allow wh-in situ either (see STOYANOVA, 2008). Irish (see e.g. McCLOSKEY, 1979), Italian (see e.g. CALABRESE, 1984), Somali, and Berber (see e.g. STOYANOVA, 2008), for instance, are typical examples of languages that disallow multiple wh-questions, as illustrated in (31)-(34), and all of them also disallow in situ wh-phrases.9

(31) Irish (McCLOSKEY, 1979)

*Cé aL rinne caidé?

who C did what

‘Who did what?’

(32) Italian (CALABRESE, 1984)

*Chi ha scritto che cosa?

who has written what

‘Who has written what?’

(33) Somali (STOYANOVA, 2008)

*yaa yimid goorma?

who-FM came time-which

‘Who came when?’

(34) Berber (STOYANOVA, 2008)

*Wiy yzrin may?

who-CM saw-PART what-CM

‘Who saw what?’

A very influential hypothesis for the lack of multiple interrogative in these languages is that their wh-phrases must move to a focus position (which is independently supported by phonological and morphological properties associated with focus found in single wh-questions), but there is only one position for focus in these languages (see e.g. CALABRESE, 1984 and STOYANOVA, 2008). Although very plausible, this hypothesis raises the question of why multiple wh-movement should be restricted in this way. After all, multiple wh-fronting languages like Serbo-Croatian exhibit just the opposite pattern: all wh-phrases must move to a focus projection (see e.g. BOŠKOVIĆ, 2002). Furthermore, from the perspective of bare phrase structure (see CHOMSKY, 1995), there is in principle nothing that bars multiple specifiers.

The proposal above in terms of minimality in fact outlines an answer for why there is only one specifier for Foc in these languages. Under the standard assumption that focus cannot be base-generated (see e.g. CINQUE, 1990), elements occupying a Spec of Foc must have reached this position via movement. However, if wh-phrases in the relevant languages are specified for EF valued as Foc ([EF:Foc]), no wh-phrase can cross (the trace of) the other without violating minimality. Furthermore, given that EF must function as a probe in order to be licensed, they cannot be licensed in situ. Hence, wh-questions in these languages must involve a single wh-phrase.

Let us now examine multiple wh-questions in languages like Brazilian Portuguese and English. Recall that Nunes (2021) has proposed that [EF:Q] is lexically optional on wh-elements in Brazilian Portuguese and on phase heads in English (see section 1). Consider Brazilian Portuguese, first. (35) illustrates the logical possibilities for multiple questions with two wh-phrases: no [EF:Q] on either WH (see (35a)); [EF:Q] on both WHs (see (35b)); [EF:Q] only on WH₂ (see (35c)); and [EF:Q] only on WH₁ (see (35d)).

(35)

a. [Q … WH₁ … WH₂ …]

b. [Q … WH_1-[EF:Q] … WH_2-[EF:Q] …]

c. [Q … WH₁ … WH_2-[EF:Q] …]

d. [Q … WH_1-[EF:Q] … WH₂ …]

If no WH in (35a) bears EF, none can undergo wh-movement, yielding a grammatical multiple wh-question with both WHs in situ, as illustrated in (36) below.10

(36) Brazilian Portuguese

Você acha que quem comprou o quê?

you think that who bought what

‘Who do you think bought what?’

If the two WHs in (35b) are specified for [EF:Q], both must move, which should give rise to a multiple wh-fronting construction. However, neither possibility in (37) below yields a grammatical output. The first movement of the object to the edge of the embedded vP, sketched in (38), is unproblematic, as both the subject and the object sit in the minimal domain of v, thus being equidistant from one another (see CHOMSKY, 1995). The problem shows up when o que is required to move to the next phase edge; as shown in (39), the instance of quem in [Spec,TP] prevents o que from moving, as they are not in the same minimal domain. Nothing changes if quem moves to the edge of CP first, as sketched in (40), for the trace of the subject counts as a proper intervener by being fully specified (see section 2.2). In other words, the ungrammaticality of the sentences in (37) are to be subsumed under the same explanation for the lack of multiple wh-questions in Irish, Italian, Somali or Berber (see section 2.2).

(37) Brazilian Portuguese

a. *Quem o que você acha que comprou?

who what you think that bought

b. *O que quem você acha que comprou?

what who you think that bought

‘Who do you think bought what?’

(38) [_vP o que_[EF:Q] [_v’ quem_[EF:Q] [ v comprou o que_[EF:Q]]]]

Figure 4

The possibility in (35c) should have an in situ wh-subject and a moved wh-object, yielding (41) below. The ungrammaticality of (41) receives the same explanation as the ungrammaticality of the sentences in (37) under the derivational route sketched in (39). Given that edge features on wh­-elements in Brazilian Portuguese are optional, the upper instance of quem in (42) counts as a proper intervener for the movement of what, for all of its features are fully specified. Movement of o que across quem in (42) thus induces a minimality/superiority effect, as seen in (41).

Figure 5

Finally, (35d) yields a grammatical output, as illustrated in (43) below. Once o que does not have EF, it stays put; quem, on the other hand, is specified as bearing [EF:Q] and moves from the embedded [Spec,TP] to the matrix [Spec,CP], passing through every phase edge on its way, as sketched in (44).

(43) Brazilian Portuguese

Quem você acha que comprou o quê?

who you think that bought what

‘Who do you think bought what?’

(44) [_CP quem_-√[EF:Q] Q [você [_vP t [v acha [_CP t que [t [_vP t [v comprou o quê]]]]]]]]

As for English multiple wh-questions, they display the Brazilian Portuguese pattern, with the only exception being that the possibility with all wh-phrases in situ is not allowed, as exemplified in (45).

(45)

a. *you think who bought what?

b. *Who what do you think bought?

c. *What who do you think bought?

d. *What do you think who bought?

e. Who do you think bought what?

Recall that wh-phrases in English are not lexically encoded with EF. So, the ungrammaticality of (45a) is not to be ascribed to the wh-phrases themselves. Furthermore, given that declarative C_Ø and v are optional EF-bearers, if they exercise their EF-less option in (45a), they won’t have EF to assign to the wh-phrases, and again no wh-movement should take place. The source of the ungrammaticality of (45a) seems to be found on the interrogative complementizer Q in English. Assuming that Q has an uninterpretable wh-feature (see e.g. BOŠKOVIĆ, 2007), it should have a wh-phrase in its domain in order to be licensed via Agree. Under the assumption that Agree is subject to the Phase Impenetrability Condition, Q in (46) is unable to check its wh-feature, as the wh-phrases are buried within the lower phases.

Figure 6

Other than this difference with respect to the matrix interrogative complementizer, the minimality computations will be exactly like the ones in Brazilian Portuguese, the only difference being that the wh-phrases may acquire EF from the local phase heads. If both the embedded C and the embedded v are each specified for EF and assign it to the wh-phrase in their probe domain, as sketched in (47) below, multiple wh-fronting should be enforced to check the two instances of EF, but what cannot move across who (or its trace) because it is fully specified (see section 2.2). Thus, sentences such as (45b) and (45c) are both ruled out.

(47)

a. [_CP Q_[wh] you [_vP v think [_CP C_Ø-[EF:Q] [who [_vP v_[EF:Q] bought what]]]]] →_{EF assignment}

b. [_CP Q_[wh] you [_vP v think [_CP C_Ø [who_[EF:Q] [_vP v bought what_[EF:Q]]]]]]

Another superiority effect arises if only the embedded v is specified for EF, as sketched in (48).

(48)

a. [_CP Q_[wh] you [_vP v think [_CP C_Ø [who [_vP v_[EF:Q] bought what]]]]] →_{EF assignment}

b. [_CP Q_[wh] you [_vP v think [_CP C_Ø [who [_vP v bought what_[EF:Q]]]]]]

In (48), what must move after it is assigned EF but who blocks its movement. Although who in (48b) has not been assigned EF, all of its features are fully specified. This renders it an appropriate intervener for the movement of what, ruling out the sentence in (45d).

The only relevant convergent output thus results from a numeration where only the embedded C is specified for EF, as sketched in (49) below. What remains in situ as it is not assigned EF and who undergoes successive cyclic movement to [Spec,Q], making it possible for who to check its EF (and for Q to check its uninterpretable wh-feature). The result is the acceptable sentence in (45e).

(49)

a. [_CP Q_[wh] you [_vP v think [_CP C_Ø-[EF:Q] [who [_vP v bought what]]]]] →_{EF assignment}

b. [_CP Q_[wh] you [_vP v think [_CP C_Ø [who_[EF:Q] [_vP v bought what]]]]]

Let us now consider languages that allow multiple wh-fronting with no superiority effects such as Serbo-Croatian (see e.g. RUDIN, 1988; RICHARDS, 2001; and BOŠKOVIĆ, 2002).

(50) Serbo-Croatian (BOŠKOVIĆ, 2002)

a. Ko koga voli

who whom loves

b. Koga ko voli

whom who loves

‘Who loves who?’

If the wh-phrases in Serbo-Croatian must all move, it is reasonable to assume that the motivation for movement (i.e. EF) is to be found on the wh-elements themselves (see BOŠKOVIĆ, 2007). However, we have already seen that if a language has all of its wh-elements inherently associated with a valued instance of EF, multiple wh-questions are actually ruled out, due to minimality/superiority (see section 3.2). We are then left with the possibility that wh-elements in a language such as Serbo-Croatian are obligatorily specified for an unvalued instance of EF ([EF:u]). By being associated with EF, the relevant wh-phrases must move to have EF checked; furthermore, by having an unvalued instance of EF, one wh-phrase will not count as a proper intervener for the other, for it is not fully specified (see section 2.2). The derivations of the sentences in (50a) and (50b), for example, share the derivational steps sketched in (51a-d) below, where the object koga moves to the edge of vP, the subject ko moves to [Spec,TP], and a Focus head is merged. Given the close-knit relation between focus and questions, it is not surprising that languages often move wh-elements to a focus position (see section 2.2). We will see evidence for such a possibility for Serbo-Croatian in section 2.5. For now, it suffices to note that by being unvalued, the EFs in (51) are not “picky”; the wh-phrases can then move to [Spec,FocP], value EF as Foc, and receive a coherent semantic interpretation. If the object koga moves first, as shown in (52), the order in (50a) is derived. If the subject moves first instead, as shown in (53), we obtain the order in (50b).

(51)

a. [_vP ko_[EF:u] [v voli koga_[EF:u]]]

b. [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]

c. [_TP ko_[EF:u] T [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]]

d. [_FocP Foc [_TP ko_[EF:u] T [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]]]

In her classical work on multiple wh-questions, Rudin (1988) observes that Bulgarian and Serbo-Croatian allow multiple wh-fronting, but only Bulgarian displays superiority effects, as illustrated in (54), which should be compared with the Serbo-Croatian data in (50).

(54) Bulgarian (RUDIN, 1988)

a. Koj kogo vižda?

who whom sees

b. *Kogo koj vižda?

whom who sees

‘Who sees whom?’

This intriguing contrast between very closely related languages has generated a lot of discussion in the literature and has been analyzed in terms of ad hoc or conceptually questionable mechanisms. In Rudin’s (1988) work, for instance, the highest wh-phrase in Bulgarian moves to [Spec,CP] and the other wh-phrases right-adjoin to it, whereas in Serbo-Croatian, the wh-phrases are taken to adjoin to IP in any order. For Bošković (1999), the relevant parameter has to do with the number of constituents a given functional head attracts: Bulgarian sets the option Attract-1, resulting in superiority effects, whereas Serbo-Croatian sets the option Attract-All, yielding no superiority effects. Finally, Richards (2001) proposes that highest wh-phrase in Bulgarian moves to [Spec,CP] and the remaining wh-phrases move to lower specifiers, “tucking in”, in violation of Chomsky’s (1995) Extension Requirement. This brief description of some of the most influential analyses of multiple wh-questions in the literature makes it clear that the topic is still in need of an approach that does not tacitly take multiple wh-question constructions as a theoretical primitive, relying on more basic properties of the system.

From the point of view of the present paper, a pattern such as (54) also looks very challenging. On the one hand, in order for all wh-phrases to be fronted, the wh-phrases must be obligatorily specified as bearing an unvalued instance of EF ([EF:u]); see section 2.4). On the other hand, minimality/superiority effects were analyzed in terms of wh-phrases bearing a valued instance of EF ([EF:val]; see sections 2.2 and 2.4); hence, the superiority effect seen in (54) should somehow involve the computation of [EF:val]. This apparent contradiction dissolves once we take into account the lexical hosts of the relevant features. It could be the case, for instance, that all wh-elements in Bulgarian are obligatorily specified for [EF:u], as in Serbo-Croatian, and the relevant [EF:val] responsible for the observed superiority effect is associated with some phase head.

Before we examine this logical possibility with respect to Bulgarian, let us consider the Serbo-Croatian data in (55).

(55)Serbo-Croatian (BOŠKOVIĆ, 2002)

a. Ko li koga voli

who C whom loves

b. *Koga li ko voli

whom C who loves

‘Who on earth loves whom?’

As discussed by Bošković (2002), Serbo-Croatian displays superiority effects when the complementizer-like element li is present. Under the reasonable assumption that it is li that is ultimately responsible for the observed superiority effect in (55), it is tempting to conjecture that Bulgarian involves a null head with the properties of Serbo-Croatian li. Let us then see the ingredients of such as analysis, taking (55) in Serbo-Croatian as a starting point.

We have seen in section 2.4 that wh-phrases in Serbo-Croatian are obligatorily specified for [EF:u], which implies that all wh-phrases must move in order to check EF and once EF is unvalued, one wh-phrase does not count as a proper intervener for the movement of another wh-phrase. So, the derivation of (55) is identical to the derivation of (50) until TP is built, as shown in (56) (cf. (51)).

(56)

a. [_vP ko_[EF:u] [v voli koga]_[EF:u]]]

b. [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]

c. [_TP ko_[EF:u] T [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]]

The next question is to determine if li should be treated as an instance of Foc or C. If it were Foc, the derivation should proceed exactly as in the derivation discussed in section 2.4, with all the wh-phrases moving past li, yielding an incorrect output (see (55a)). So, the conclusion is that li should be analyzed as C on top of FocP. In other words, multiple wh-fronting in (55) still targets [Spec,FocP], as in the version without li (see (50)), but it is coupled with an additional movement (of the highest wh-phrase) to [Spec,CP]. Given that in this system, overt A’-movement is triggered by EF, one wonders whether li could be obligatorily specified as [EF:Q] and assign it to a wh-phrase in its domain, attracting it to its Spec. There are reasons to assume that this possibility is not available, though.

First, the Anti-Locality Restriction on Feature Bundling in (57) below, proposed by Nunes (2020), excludes the specification li_[EF:Q] if li is an interrogative complementizer in (55). The rationale behind (57) is that the role of EFs is to establish a relation that would otherwise be blocked by the Phase Impenetrability Condition (see section 1). In a system that allows syntactic relations to be established by Agree only (without movement), EF should be postulated just in case it wouldn’t be vacuous. This is exactly the effect of (57). In the present case, if li has a [-interpretable] wh-feature (like English interrogative Q; see section 1), this suffices for li to be able to establish a relation with a wh-phrase in its domain, with no need to trigger movement of this constituent.

(57) (NUNES, 2021)

Anti-locality Restriction on Feature Bundling: *X_[EF:X]

A given functional category X cannot be lexically associated with an edge feature valued as X.

A second reason not to associate li with an EF is that it is not trivial how to restrict movement to the highest wh-phrase. Crucially, the subject and the object can occupy the outer [Spec,FocP], as seen in (50).

The conclusion is that Foc is the lexical host of [EF:Q], not li. This is not unprecedented, though. Nunes (2021) has reinterpreted anti-that-trace effects such as the one illustrated in (58) below exactly in these terms. Recall that declarative that in English is not specified for EF (see (12a)) and this is what ultimately prevents local subject extraction (see (14) and section 1). That being so, Nunes proposes that the head H that hosts the adverbial in (58) is specified for [EF:Q] and assigns it to the embedded subject which can then undergo successive cyclic movement despite the inertness of that, as sketched in (59).11

(58) (CULICOVER, 1993)

I asked what_i Leslie said that *(in her opinion) t_i had made Robin give a book to Lee.

(59)

a. [_CP that [_HP [in her opinion] H_[EF:Q] [_TP what had made …]]] →_{EF-assignment}

b. [_CP that [_HP [in her opinion] H [_TP what_[EF:Q] had made …]]]

c. [_CP what_[EF:Q] that [_HP [in her opinion] H [_TP t had made …]]]

Foc in Serbo-Croatian must be optionally specified as bearing [EF:Q]. If it doesn’t bear this specification, we have derivations like the one discussed in section 2.4, with multiple wh-fronting and no superiority effects (see (52) and (53)). Let us then see how the derivation unfolds when Foc is specified as bearing [EF:Q]. After the derivational step in (60a) below is reached, the subject wh-phrase is the closest potential target for EF-assignment. Foc then assigns EF to the subject, yielding (60b).12

(60)

a. [_FocP Foc_[EF:Q] [_TP ko_[EF:u] T [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]]] →_{EF-assignment}

b. [_FocP Foc [_TP ko_{[EF:u]-[EF:Q]} T [_vP koga_[EF:u] [ko_[EF:u] [v voli koga_[EF:u]]]]]]

The higher instance of ko in (60b) is not fully specified as it still has an unvalued instance of EF. Thus, the object can move across it and value its own EF, as shown in (61a) below. The subject can then move the outer [Spec,FocP], valuing its unvalued EF, yielding (61b). Crucially, although the object in the inner [Spec,FocP] is fully specified, the subject moves to the minimal domain that includes the object (CHOMSKY, 1995). Finally, after li enters the structure in (61c), it licenses its wh-feature via Agree, as shown in (61d), and the subject moves to [Spec,CP] to check the edge feature it has received from Foc, as shown in (61e), yielding the surface order in (55a).

Figure 8

Suppose instead that after the derivational stage in (60b) is reached, the subject moves to [Spec,FocP] before the object, as represented in (62a). The object then moves from [Spec,vP] to [Spec,FocP], as shown in (62b), without violating minimality: the copy of ko in [Spec,TP] is not fully specified as it has an unvalued EF and the higher copy is fully specified but is equidistance from the moved object. The subject in the inner [Spec,FocP] then moves to [Spec,li] to license the edge feature it has received from Foc in (60b), as shown in (62c), and the crossed object in the outer [Spec,FocP] does not intervene due to equidistance. Interestingly, the final order of the output is again the one that complies with superiority (see (55a)), but the superiority effect stems not from movement (the object actually crosses the subject in (62b)), but from EF-assignment (Foc in (60) assigns its EF to the closest appropriate element in its domain – the wh-subject).

Figure 9

Returning to the Bulgarian data in (54), their derivations will be essentially like the ones discussed regarding the Serbo-Croatian data with li in (55), the only difference being a null C with a [-interpretable] wh-feature instead of li. To put things in broad terms, the discussion above shows that superiority effects in multiple wh-questions show up depending on the lexical locus of EFs and their values; different results may arise even within the same language depending on how these possibilities are fixed.