Complementizer
In linguistics, a complementizer or complementiser is a functional category that includes those words that can be used to turn a clause into the subject or object of a sentence. For example, the word that may be called a complementizer in English sentences like Mary believes that it is raining. The concept of complementizers is specific to certain modern grammatical theories. In traditional grammar, such words are normally considered conjunctions. The standard abbreviation for complementizer is C.
Category of C
C as head of CP
The complementizer is often held to be the syntactic head of a full clause, which is therefore often represented by the abbreviation CP. Evidence of the complementizer functioning as the head of its clause includes that it is commonly the last element in a clause in head-final languages like Korean or Japanese in which other heads follow their complements, but it appears at the start of a clause in head-initial languages such as English in which heads normally precede their complements.The trees below illustrate the phrase "Taro said that he married Hanako" in Japanese and English; syntactic heads are marked in red and demonstrate that C falls in head-final position in Japanese, and in head-initial position in English.
C can develop from a determiner
Across world languages, pronouns and determiners are especially commonly used as complementizers.C can develop from an interrogative word
Another frequent source of complementizers is the class of interrogative words. It is especially common for a form that otherwise means what to be borrowed as a complementizer, but other interrogative words are often used as well, as in the following colloquial English example in which unstressed how is roughly equivalent to that.C can develop from a preposition
With non-finite clauses, English for in sentences like I would prefer for there to be a table in the corner shows a preposition that has arguably developed into a complementizer.C can develop from a verb
In many languages of West Africa and South Asia, the form of the complementizer can be related to the verb say. In those languages, the complementizer is also called the quotative, which performs many extended functions.Empty complementizers
Some analyses allow for the possibility of invisible or "empty" complementizers. That is considered to be present if there is no word even though the rules of grammar expect one. The complementizer is usually said to be understood. An English-speaker knows that it is there and so it does not need to be said. Its existence in English has been proposed based on the following type of alternation:Because that can be inserted between the verb and the embedded clause without changing the meaning, the original sentence without a visible complementizer would be reanalyzed as
Where the symbol ∅C represents the empty complementizer, that suggests another interpretation of the earlier "how" sentence:
where "how" serves as a specifier to the empty complementizer, which allows for a consistent analysis of another troublesome alternation:
where "OP" represents an invisible interrogative known as an operator.
In a more general sense, the proposed empty complementizer parallels the suggestion of near-universal empty determiners.
Various analyses have been proposed to explain when the empty complementizer ∅ can substitute for a phonologically overt complementizer. One explanation is that complementizers are eligible for omission when they are epistemically neutral or redundant. For example, in many environments, English's [|epistemically neutral] that and Danish's at can be omitted. In addition, if a complementizer expresses a semantic meaning that is also expressed by another marker in the phrase, the complementizer that carries the redundant meaning may be omitted. Consider the complementizer be in Mbula, which expresses uncertainty, in the following example:
Here, the marker ko also expresses epistemic uncertainty, so be can be replaced by the phonologically null complementizer without affecting meaning or grammaticality.
Complementizers are present in a wide range of environments. In some, C is obligatorily overt and cannot be replaced by the empty complementizer. For example, in English, CPs selected for by manner-of-speaking verbs resist C-drop:
In other environments, the complementizer can be omitted without loss of grammaticality but may result in semantic ambiguity. For example, consider the English sentence "The newspaper reported that a new mayor was elected and ' there was a riot." Listeners can infer a causal relationship between the two events reported by the newspaper. A new mayor was elected, and as a result, there was a riot. Alternatively, the events may be interpreted as independent of each other. The non-causal interpretation is more likely when the second complementizer that' is present, but the causal interpretation is more likely when an empty complementizer is present.
The ambiguity here arises because the sentence in which the second complementizer is empty may also be interpreted as simply having no second complementizer. In the former case, the sentence involves co-ordination of CPs, which lends itself more easily to a non-causal interpretation, but the latter case involves co-ordination of TPs, which is the necessary structure for a causal interpretation. Partial syntax trees for the possible structures are given below.
Selectional restrictions imposed by C
As a syntactic head, C always selects for a complement tense phrase whose syntax and semantics are dictated by the choice of C. The choice of C can determine whether the associated TP is finite or non-finite, whether it carries the semantic meaning of certainty or uncertainty, whether it expresses a question or an assertion, etc.Propositions vs. indirect questions
The following complementizers are available in English: that, for, if, whether, ∅.If and whether form CPs that express indirect questions:
In contrast, the complementizers for, that, as well as the phonologically null complementizer ∅, introduce "declarative or non-interrogative" CPs.
Finite vs. non-finite TPs
Tense phrases in English can be divided into finite clauses or non-finite clauses. The former includes an indication of the relative time when its content occurs; the latter has no overt indication of time. Compare John will leave with John wants to leave.Certain complementizers strictly select for finite clauses while others select for non-finite clauses.
Complementizers if, that require TP:
Complementizer for requires a TP:
Complementizer whether allows either or TP:
| Category | Sub-category | English examples | Number |
| Complementizer | finite C | n = 5 | |
| non-finite C | |||
| interrogative C |
Epistemic selection
Complementizers frequently carry epistemic meaning about the speaker's degree of certainty, such as whether they are doubtful, or the speaker's source of information, such as whether they are making an inference or have direct evidence. Contrast the meaning of "if" and "that" in English:"If" signals that the associated tense phrase must carry the epistemic meaning of uncertainty. In contrast, "that" is epistemically neutral. The contrast is not uncommon cross-linguistically. In languages with only two complementizers, one is frequently neutral, and the other carries the meaning of uncertainty. One such language is Lango :
Additional languages with the neutrality/uncertainty complementizer contrast include several European languages:
| Language | Neutral complementizer | Uncertain complementizer |
| Faroese | at | um |
| Neo-Aramaic | ||
| Bulgarian | ||
| Estonian | et | kas |
| Irish | go | an |
In other languages, complementizers are richer in epistemic meaning. For example, in Mbula, an Austronesian language of Papua New Guinea, the following complementizers are available:
| Complementizer | Epistemic meaning |
| kokena be / ∅ | 'lest' |
| kembei | 'like' |
| ∅ | 'asserted factuality' |
| ta / ∅ | 'presupposed factuality' |
| tabe | 'presupposed non-factuality' |
| ki | 'habitual event' |
More generally, complementizers have been found to express the following values cross-linguistically: certainty, uncertainty, probability, negative probability/falsehood, apprehension, and reportativity.
Complementizers in Itzaj Maya also demonstrate epistemic meaning. For instance, English that and Itzaj Maya kej are used not only to identify complements but also to introduce relative clauses:
introduces a subordinate clause and introduces a conditional clause, similar to English. The former subtype that can be defined in terms of information source and includes meanings glossed as direct evidence, indirect evidence, hearsay, inferential. The latter subtype if can be defined in terms of degree of certainty and includes meanings glossed as certainty, probability, epistemic possibility, doubt. Thus, epistemic meaning as a whole can be defined in terms of the notion of justificatory support.
Complementizer stacking
Itzaj Maya can even combine the neutral complementizer, ke, with the non-neutral, waj, as is illustrated in examples in which the neutral complementizer ke occurs alone and in which it is optionally inserted in front of the uncertainty complementizer waj:In and, each complementizer can be licensed once within the clause, but in, the significant difference of Itzaj Maya from English is observed. English can license multiple C as long as the clause is completed with the embedded V or D. For example, I saw that fox that ran towards the garden that Tommy took care of. In such cases, C can appear as the complement of V or D many times. However, CP-recursion in two tiers or CP appearing as an immediate complement of maximal projection CP cannot be allowed in English. That action of Complementizer Stacking is realised as ungrammatical.
In Scandinavian languages, however, the phenomenon of complementizer stacking occurs. For example, researchers observed the two basic types of CP-recursion that occur independently in Danish: a CP with V2 will be referred as CP, and a CP without V2 will be referred to as cP.
The case of little/big CPs are comparable to the "VP shell" structure in English, which introduces a small v in the higher position in the tree and big V in the lower position in the tree.
In the examples, Danish also allows complementizer stacking in constructions involving [subject (grammar)">subject extraction from complement and [relative clauses">– LEXICAL
In the examples, Danish also allows complementizer stacking in constructions involving [subject (grammar)">subject extraction from complement and [relative clauses in colloquial speech:
Complementizers are indeed stacked together in the beginning of the clause and act as a complement of DP. CP-recusion structure on the right is applied for each of the clause, which points to evidence of complementizer stacking in Danish. In addition, the combination of som at der in is possible in only one specific order, which led the researchers to believe that som may not require an empty operator in its Spec-CP position.
In various languages
Assyrian Neo-Aramaic
In Assyrian Neo-Aramaic, a modern Aramaic language, is used as a complementizer and is related to the relativizer. It is less common in casual speech but more so in formal conversation.Hebrew
In Hebrew, four complementizers co-exist:1. שֶ. It is related to the formal relativizer asher
2. אשר after a noun
3. הַ after a noun and before a present tense verb
4. כִּי after a verb
In modern usage, only ש is used in everyday speech, while all other forms are reserved for more formal writing.