Merge is one of the basic operations in the Minimalist Program, a leading approach to generative syntax, when two syntactic objects are combined to form a new syntactic unit (a set). Merge also has the property of recursion in that it may be applied to its own output: the objects combined by Merge are either lexical items or sets that were themselves formed by Merge. This recursive property of Merge has been claimed to be a fundamental characteristic that distinguishes language from other cognitive faculties. As Noam Chomsky (1999) puts it, Merge is "an indispensable operation of a recursive system ... which takes two syntactic objects A and B and forms the new object G={A,B}" (p. 2).Chomsky (1999).
Mechanisms of Merge
Within the Minimalist Program, syntax is derivational, and Merge is the structure-building operation. Merge is assumed to have certain formal properties constraining syntactic structure, and is implemented with specific mechanisms. In terms of a merge-base theory of language acquisition, complements and specifiers are simply notations for first-merge (read as "complement-of" [head-complement]), and later second-merge (read as "specifier-of" [specifier-head]), with merge always forming to a head. First-merge establishes only a set {a, b} and is not an ordered pair. In its original formulation by Chomsky in 1995 Merge was defined as inherently asymmetric; in Moro 2000 it was first proposed that Merge can generate symmetrical structures provided that they are rescued by movement and asymmetry is restored ). For example, an {N, N}-compound of 'boat-house' would allow the ambiguous readings of either 'a kind of house' and/or 'a kind of boat'. It is only with second-merge that order is derived out of a set {a {a, b}} which yields the recursive properties of syntax. For example, a 'House-boat' {house {house, boat}} now reads unambiguously only as a 'kind of boat'. It is this property of recursion that allows for projection and labeling of a phrase to take place; in this case, that the Noun 'boat' is the head of the compound, and 'house' acting as a kind of specifier/modifier. External-merge (first-merge) establishes substantive 'base structure' inherent to the VP, yielding theta/argument structure, and may go beyond the lexical-category VP to involve the functional-category light verb vP. Internal-merge (second-merge) establishes more formal aspects related to edge-properties of scope and discourse-related material pegged to CP. In a Phase-based theory, this twin vP/CP distinction follows the "duality of semantics" discussed within the Minimalist Program, and is further developed into a dual distinction regarding a probe-goal relation. As a consequence, at the "external/first-merge-only" stage, young children would show an inability to interpret readings from a given ordered pair, since they would only have access to the mental parsing of a non-recursive set. (See Roeper for a full discussion of recursion in child language acquisition).). In addition to word-order violations, other more ubiquitous results of a first-merge stage would show that children's initial utterances lack the recursive properties of inflectional morphology, yielding a strict Non-inflectional stage-1, consistent with an incremental Structure building model of child language.).
Binary branching Merge takes two objects α and β and combines them, creating a binary structure.
Feature checking In some variants of the Minimalist Program Merge is triggered by feature checking, e.g. the verb eat selects the noun cheesecake because the verb has an uninterpretable N-feature [uN] ("u" stands for "uninterpretable"), which must be checked (or deleted) due to full interpretation.See Adger (2003). By saying that this verb has a nominal uninterpretable feature, we rule out such ungrammatical constructions as *eat beautiful (the verb selects an adjective). Schematically it can be illustrated as:
Strong features There are three different accounts of how strong features force movement:
1. Phonetic Form (PF) crash theory (Chomsky 1993) is conceptually motivated. The argument goes as follows: under the assumption that Logical Form (LF) is invariant, it must be the case that any parametric differences between languages reduce to morphological properties that are reflected at PF (Chomsky 1993:192). Two possible implementations of the PF crash theory are discussed by Chomsky: if a strong feature is visible at PF after Spell-out, because it is not a legitimate PF object, the derivation crashes (Chomsky 1993:198); PF rules do not apply to undeleted strong features, and so the derivation crashes (Chomsky 1993:216)
PF crash theory: A strong feature that is not checked in overt syntax causes a derivation to crash at PF. 2. Logical Form (LF) crash theory (Chomsky 1994) is empirically motivated by VP ellipsis. LF crash theory: A strong feature that is not checked (and eliminated) in overt syntax causes a derivation to crash at LF. 3. Immediate elimination theory ((Chomsky 1995)) Virus theory: A strong feature must be eliminated (almost) immediately upon its introduction into the phrase marker; otherwise, the derivation cancels.
Pseudogapping and sluicing, the two ellipsis components, verify the relevance of strong features provided by Chomsky (1993). The usage of a strong feature enables movement or ellipsis to save a derivation. Raising that is prompted by strong features generate ellipsis. Strong features include the Extended Projection Principle and the split VP hypothesis. PF crash theory is pertinent through direct or indirect mechanisms. Strong features prompt overt movement. Under the PF crash theory, all of the constituents, not just formal features, must move by means of pied-piping.
Constraints Initially, the cooperation of Last Resort (LR) and the Uniformity Condition (UC) were the indicators of the structures provided by Bare Phrase which contain labels and are constructed by move, as well the impact of the Structure Preservation Hypothesis. The Uniformity Condition, with respect to the phrase structure status, is an unchanging chain. It has three functions that contributes to the idea of movement:
It obstructs the movement of a minimal non maximal projection to a specifier. It obstructs the covert movement of formal features (FF) to a specifier. It averts a moved non minimal projection from projecting further subsequent to merging with its target. C-command: In order to maintain the desired simplicity of the Minimalist Program, c-command gains it recognition as being more optimal, and therefore replaces the Uniformity Condition for two reasons:
Methodologically, the majority of existing relations contain C-command as its foundation. The condition of c-command on chain links posits a restriction regarding the movement of intermediate projections, unlike the Uniformity Condition. Last Resort is a property of Move: feature may move to its target only if the moved feature enters a checking relation with a feature of the head it is moving to. For example, D may move to SPEC C, only if the maximal projection and its subsequent projection select for D. The Minimal Link Condition (MLC) is a second important property of Move. According to the MLC, a feature can only move to its target if there is no prior feature that is able to move under the Last Resort property and is closer to the target than the original feature. (e.g. C cannot move to target A if B obeys the Last Resort and is closer to target A than C).
Projection and labeling When we consider the features of the word that provide the label when the word projects, we assume that the categorical feature of the word is always among the features that become the label of the newly created syntactic object. In this example below, Cecchetto demonstrated how projection selects a head as the label.
In this example by Cecchetto (2015), the verb "read" unambiguously labels the structure because "read" is a word, which means it is a probe by definition, in which "read" selects "the book". the bigger constituent generated by merging the word with the syntactic objects receives the label of the word itself, which allow us to label the tree as demonstrated.
In this tree, the verb "read" is the head selecting the DP "the book", which makes the constituent a VP.
No tampering condition (NTC) Merge operates blindly, projecting labels in all possible combinations. The subcategorization features of the head act as a filter by admitting only labelled projections that are consistent with the selectional properties of the head. All other alternatives are eliminated. Merge does nothing more than combine two syntactic objects (SO's) into a unit, but does not affect the properties of the combining elements in any way. This is called the No Tampering Condition (NTC). Therefore, if α (as a syntactic object) has some property before combining with β (which is likewise a syntactic object) it will still have this property after it has combined with β. This allows Merge to account for further merging, which enables structures with movement dependencies (such as wh-movement) to occur. All grammatical dependencies are established under Merge: this means that if α and β are grammatically linked, α and β must have merged.
Bare phrase structure (BPS) A major development of the Minimalist Program is Bare Phrase Structure (BPS), a theory of phrase structure (structure building operations) developed by Noam Chomsky in 1994.See Chomsky, Noam. 1995. Bare Phrase Structure. In Evolution and Revolution in Linguistic Theory. Essays in honor of Carlos Otero., eds. Hector Campos and Paula Kempchinsky, 51–109. BPS is a representation of the structure of phrases in which syntactic units are not explicitly assigned to categories. The introduction of BPS moves the generative grammar towards dependency grammar (discussed below), which operates with significantly less structure than most phrase structure grammars.Osborne, Timothy, Michael Putnam, and Thomas Gross 2011. Bare phrase structure, label-less structures, and specifier-less syntax: Is Minimalism becoming a dependency grammar? The Linguistic Review 28: 315–364 The constitutional operation of BPS is Merge. Bare phrase structure attempts to: (i) eliminate unnecessary elements; (ii) generate simpler trees; (ii) account for variation across languages.
Bare Phrase Structure defines projection levels according to the following features: X+max is the maximal projection; the lexical category cannot project to any further point in the tree X+min is the minimal projection, and corresponds to the lexical item without any of its associated projects (if any) X-max,-min lies between minimal and maximal projection( this corresponds to the intermediate projection level in X-bar Theory) the complement position is the sister to X+min the specifier position is the sister to the intermediate projection X-max,-min
Maximal ProjectionMinimal ProjectionIntermediate Projection
Fundamental properties The minimalist program brings into focus four fundamental properties that govern the structure of human language: