Otsuka (2005) proposes an account for Tongan that includes T-to-C movement. Her analysis for the verb-initial order in the language is based in a head-movement approach, where it is proposed that the verbal head undergoes V-to-T-to-C movement. The reason for positing V-to-T movement is that Tongan exhibits argument scrambling, allowing both VSO and VOS sentences, as in (1a–1b) respectively.

Following Chomsky (1993), Otsuka asserts that if V moves to T, the subject and object are equidistant from T˚. She proposes T˚ contains an EPP feature, which draws the closest DP to the specifier position of TP, under the Minimal Link Condition (Chomsky 1995). Since V-to-T movement renders both arguments equidistant from T˚, this allows either argument to raise to SpecTP. VSO clauses involve the subject DP raising to SpecTP, whereas VOS clauses involve the object DP moving. In either case, one DP is moved to the specifier of TP. Inorder to derive the verb-initial word order, the verb must raise higher that the DP in SpecTP, hence why Otsuka argues for the verb to move further to C.

While there are independent reasons to question the validity of the V-to-T-to-C movement proposed by Otsuka, such as the issue of leftward head adjunction,2 the main point is that T-to-C movement is required in Otsuka’s analysis to obtain TAM-initial ordering.

Another argument for T-to-C movement is that complementizers and TAM particles cannot co-occur together. Custis (2004) argues that this complementary distribution results from the TAM and complementisers competing for the same syntactic slot (C˚). This distribution is shown for Tongan in (2).3 The complementiser ‘o introduces the embedded clause, which does not, and cannot, contain a TAM particle. As all other verbal clauses contain a TAM particle, it is argued that this slot is already filled by the complementiser ‘o, and thus no overt TAM particle is possible.

Note the presence of “the pronominal subject” occurring pre-verbally, a common occurrence in Polynesian languages, which will play a significant role in the rest of this squib.

Collins (2017) investigates Samoan verb-initial order and posits T-to-C movement for several reasons. First, Collins demonstrates that Samoan TAM markers appear to show properties related to both T and C.5 For instance, in relative clauses, a TAM particle precedes the relative clause, and therefore is interpreted as a relativizing complementiser.

Furthermore, Collins notes that the complementiser ona is in complementary distribution with TAM particles. When a verb takes the complementiser ona, the embedded verb may not be preceded by any TAM marker. This leads Collins to argue that T˚ and C˚ are syntactically merged, having undergone T-to-C movement.6

In addition, T-to-C movement in Samoan is needed to understand the distribution of preverbal subject pronouns. Like Tongan, Samoan also has subject pronouns occurring preverbally in transitive sentences. Collins analyses these subject pronouns as moving to SpecTP from their base-generated position in vP. In this analysis, a variant of the English EPP[+DP] feature is on T˚, which targets weak pronominals, raising them to SpecTP. On the surface, agent pronouns precede the verb but follow the TAM marker, meaning the TAM marker must be positioned higher up in the syntax than SpecTP, where the agent pronoun is.

Under a T-to-C analysis, TAM raises out of TP, meaning the subject pronoun in SpecTP will follow the TAM particle in the surface order. Without T-to-C movement, TAM remains in T˚, while the subject pronoun raises to SpecTP, which would mean the subject would precede the TAM particle, rather than follow it. T-to-C movement therefore provides an explanation for the TAM-initial word order in Samoan.

Note that all of these previous accounts assume a simple clause periphery, with the C head taking TP as a complement, which is what this squib will call into question. I will propose that a single CP cannot account for the data seen in these languages.

In each language above, one critical piece of evidence for T-to-C movement is that TAM particles and complementisers are in complementary distribution with one another, and as such will never co-occur. According to Custis (2004: 122) and Collins (2017: 30) (though not Otsuka), TAM only raises to C˚ when C˚ is unfilled. However, when C˚ contains an overt complementiser, T-to-C movement is blocked, and a TAM particle cannot be overt. Here I will present novel data from Tokelauan, another verb-initial Polynesian language, which illustrates that TAM particles and complementisers can co-occur.

Tokelauan has a complementiser particle pe, which introduces embedded indirect question clauses. Pe appears before the complement of a verb of knowledge, and translates roughly as ‘if’ or ‘whether’. This complementiser can introduce verbal predicates, as well as nominal predicates (Hooper 1993: 277). As illustrated below, pe can occur with a subordinate finite clause, where a TAM marker is present within the embedded clause.

The ability for both the complementiser and TAM marker to coexist within one clause demonstrates they are not in complementary distribution. Furthermore, it can be shown that C and T are not simply combined as a syntactic complex head, after undergoing T-to-C movement. If the TAM marker and complementiser are somehow adjoined, it should not be possible to split them with a phrase. In (7) and (8) the complementiser and TAM particle are separated by a ko-topicalised phrase. This is a maximal projection, which therefore cannot be argued to be a clitic attaching within a morphologically merged C˚ and T˚.

This is not an isolated example. Examining the literature, we come across several cases of complementisers and TAM co-occurring, with phrasal units in-between. In (9), the complementiser kāfai ‘if’ is followed by a ko-marked topic and then TAM, while in (10) and (11) the complementiser is followed by an adverb and then the TAM particle.

This data confirms that TAM cannot raise to C˚ if C˚ is the only complementiser position, as TAM can co-occur with complementisers. It is also worth noting that the word orders which prompted Collins (2017) and Otsuka (2005) to propose T-to-C movement also occur in Tokelauan. The basic word order of Tokelauan is VSO, but VOS alternations are possible for some speakers, similar to Tongan:

Additionally, like Samoan, an agent subject may be expressed as a pronoun, which intervenes between the TAM particle and the verb:

In the analyses of Tongan and Samoan by Otsuka (2005) and Collins (2017) respectively, the alternating VSO/VOS word order and the presence of pre-verbal subject pronouns was evidence of DP-movement to SpecTP, due to an EPP feature on T˚. Without making claims about the syntax of VSO/VOS and pre-verbal subject pronouns in Tokelauan, if either results in an argument situated in SpecTP, there is reason to suggest that TAM does raise from T˚, although the C domain requires expansion to rescue this movement, as will be argued for later in this squib.

Like Tokelauan, there is evidence that certain complementisers and TAM particles can co-exist in both Tongan and Samoan, indicating that T-to-C movement needs revisiting in these languages as well.

Samoan has two complementisers that can occur with TAM particles. Like Tokelauan, verbs of cognition or perception can introduce interrogative subordinate clauses, with the complementiser po or pe.

Matrix clauses which introduce an ina complement also optionally allow TAM makers to follow the complementiser:

Likewise, Tongan also has complementisers and TAM particles co-occurring.

As was seen in Tokelauan, it is possible to split C and TAM markers in Tongan with other morphological material, as seen below with a negative particle.8

To rule out the possibility that the negative particle could be a clitic (and thus creating a complex head C-NEG-T), and to provide support that T and C are indeed independent in Tongan, consider the following argument. Tongan exhibits a noteworthy conditional structure, the ka-ka construction, which involves a pronominal clitic intervening between a complementiser and a (phonologically identical) TAM particle (Ball 2008):

In this construction, the complementiser is able to host a subject clitic (Ball 2008: 157), which indicates the complementiser is a freestanding (unbound) morpheme.

Crucially, the TAM particle in Tongan also has the ability to host subject clitics, meaning it too is a morphologically independent word. Tongan subject clitics also surface between the TAM particle and the verb (Otsuka 2005). On the basis of prosody, subject clitics are shown by Custis (2004) to attach to the TAM, as there is a stress shift when the clitic appears between the TAM marker and the verb.

This stress pattern clarifies that the clitic has attached to the TAM marker, which is only possible if the TAM marker is a freestanding morpheme. Note it is not possible that TAM is itself a clitic which combines with the subject clitic/complementiser to form an independent word, as TAM can be found without a complementiser or subject clitic, as in (1). In this case the TAM particle would have no host to attach to.

In (19) and (20) there is clear evidence that the complementiser is a freestanding morpheme, while in (21) there is support that the TAM is also a free morpheme. Combining these two pieces of information means that when both the complementiser and TAM marker are observed co-occurring, we would have to assume that C˚ and T˚ are independent heads in Tongan, which provides evidence against a [T + C] complex head.

To sum up, this section has provided evidence that complementisers and TAM particles can co-occur, and that they are each a separate morphological entity that exists independently from each other. This is supported by examples where phrasal constituents can separate the two, which rules out the possibility that T˚ and C˚ form a complex morphological head. Furthermore, in Tongan, it was seen that both T˚ and C˚ can host clitics, which further supports an analysis that they are independent particles in the language.