- Explain why a finite clause is analyzed as an IP containing a VP rather than simply as a VP.
- Use the positions of modals, negation, and sentence-medial adverbs to motivate functional structure.
- Describe subject movement from spec-VP to spec-IP and compare copy and trace accounts.
- Explain how idioms and floating quantifiers support the VP-internal subject hypothesis.
- Represent clauses with silent tense and embedded clauses introduced by complementizers.
- Distinguish substitution, movement, and adjunction in clause construction.
- The X-bar schema and projection from a head
- Heads, complements, specifiers, and arguments
- Basic VP structure
From Verb Phrase to Inflection Phrase
A simple VP analysis is replaced by a layered IP analysis once modals and auxiliaries are considered.
Because phrases project from heads, we can ask which head projects an entire clause. One plausible starting point is the verb. On that account, the structure previously labeled S would instead be a VP, while the constituent formerly called VP would be the smaller V-bar projection. This works naturally for a basic clause such as Donald forgot Pauline's name: forgot heads the projection, with Donald and Pauline's name as its arguments.
More elaborate clauses expose a weakness in this proposal. In Iris will paint the door, the modal will occurs together with the main verb paint. Since modals and auxiliaries such as have and be resemble verbs and carry tense-related information, we might treat each as a verbal head whose complement is another VP. This would create a recursive sequence of verbal projections.
Modals behave differently from ordinary verbs, however. They occur only in finite forms: English has no infinitive can in a sequence such as it would be nice to can swim, and can and will have no past-participle forms. A modal requires a following non-finite verb, so one modal cannot take another modal-headed phrase as its complement in standard English. The proposed structure is therefore not genuinely recursive.
We call this category I, for inflection, because it is associated with tense and agreement. Some analyses use T for tense instead, but here the head is I. By the X-bar schema, an I head such as will projects I-bar and IP, and its complement is a VP. The clause is consequently an IP that contains a VP.
IP
├── I: will
└── VPOrdering Evidence from Negation and Adverbs
The position of modals relative to negation and medial adverbs distinguishes I from the VP containing the main verb.
English modals appear before sentential negation, whereas main verbs cannot occupy that position in modern English.
- Iris will not paint the door is grammatical.
- Iris paints not the door is ungrammatical in modern English.
Sentence-medial adverbs reveal the same contrast. Although adverbs can also occur at the beginning or end of a clause, a medial adverb may follow a modal directly but cannot intervene between a main verb and its direct object.
- Arthur may quickly open the tin is grammatical.
- Arthur opened quickly the tin is ungrammatical.
Negation can therefore be analyzed as another functional head, Neg, which projects NegP and selects VP. The I head may select either NegP or VP. With Neg positioned between I and VP, the modal precedes negation while the main verb remains below it inside VP.
IP → I (modal) → NegP → VPIf a language placed negation after its main verb, how might its structure differ from the English hierarchy shown here?
The Subject Begins Inside VP
The subject receives its thematic role within VP and then moves to the IP specifier.
The position of the subject creates a further problem. In Donald may forget Pauline, Donald receives its participant role from forget, not from the possibility modal may. The modal also has scope over the complete proposition: the sentence means that it is possible for Donald to forget Pauline. Thus the subject belongs with the verb in VP, inside the material over which the modal takes scope.
Substitution alone would place that subject at the left edge of VP, after the modal, producing the wrong order for a declarative clause. Yet the subject also has a grammatical relation with inflection. Agreement makes this visible with auxiliaries: the children are playing is possible, while the children is playing is not, even though play assigns the subject its thematic role.
- Construct VP with the subject in spec-VP, where the verb selects it.
- Add IP above VP and place the modal in I.
- Move the subject into spec-IP, where it can enter an agreement relation with I.
This derivation puts the pronounced subject before the modal while preserving its original connection to the verb.
Two Accounts of What Movement Leaves Behind
- Under copy theory, movement creates a higher copy while the original remains below. Repeated movement can form a chain, and normally only its highest member is pronounced.
- Under trace theory, the lower position contains an inherently silent trace. A matching subscript can identify the moved phrase associated with it.
These proposals can make different empirical predictions, but that distinction is not needed here. For the present analysis, both express the essential claim that a phrase first occupies its selected position and can later move higher in the tree.
Evidence That Subjects Originate in VP
Sentential idioms and stranded quantifiers point to a lower starting position for subjects.
Idioms with a Variable Middle
Some idioms require a particular subject and verb phrase but allow the intervening modal or auxiliary to change. Alongside heads will roll, we can have heads may roll, heads have rolled, and heads have been rolling without losing the idiomatic interpretation. The same pattern is found in the shit hit the fan.
This follows if the memorized idiom is a VP containing its subject. The subject begins inside the VP with the verb, while the modal in I lies outside the stored idiomatic unit and can vary.
Floating Quantifiers
- In All the workers may leave, all the workers moves as one constituent.
- In The workers may all leave, the workers occurs before the modal while all remains after it.
The sequence the workers all cannot answer who left? in the second pattern, showing that it is not a single constituent there. One analysis begins with all and the workers together in spec-VP. Either the complete phrase moves, or only the workers moves and strands all. The stranded quantifier marks the subject's initial location after the modal and immediately before the verb.
Could comparable quantifier stranding provide evidence for movement from an object position?
Finite Clauses with No Overt Modal
Clauses containing only a finite main verb remain IPs because tense occupies I silently.
A clause such as Iris painted the door has the same distribution as a clause containing a modal, so it should not belong to a different syntactic category. Both are IPs. In a simple finite clause, past or present tense itself occupies I, although this tense head is silent in English.
The silent head affects the verb form inside its VP complement. A past-tense I selects a past-tense form, while a present-tense I selects a present-tense form, just as a modal selects the bare infinitive. The exact relation between tense and the verb differs across languages.
[IP subject [I-bar [I past] [VP subject <verb> … ]]]As before, the subject starts inside VP and raises to spec-IP. This produces one consistent analysis for finite clauses with and without an overt modal.
Adding a Complementizer Layer
Embedded clauses may be introduced by C, which projects CP over IP.
- Ian thought Betsy would never go to Peru.
- Ian thought that Betsy would never go to Peru.
English may omit that in this environment, although corresponding elements are obligatory in many languages. The words that and if belong to the functional category Complementizer, abbreviated C. They identify a clause as subordinate and also signal its type: that introduces a subordinate declarative, while if introduces an embedded yes-no interrogative, as in she wondered if Betsy was going to Peru.
[CP [C that] [IP Betsy would never go to Peru]]Clause structure can therefore contain the layers CP above IP above VP. CP forms the outer layer used especially for embedded clauses; a root clause may also have an unpronounced C layer.
Building Modifier Structure with Adjunction
Adjunction adds unselected modifiers recursively while preserving the category of the modified phrase.
Arguments belong in the elementary structure of the head that selects them, but modifiers do not. A verb does not select the many possible expressions of time, reason, or beneficiary that can modify its VP. Since a phrase can contain a nearly unlimited number of modifiers, listing positions for all of them in each lexical structure would be inappropriate.
Adding a modifier leaves the category unchanged. John ate a banana is a VP; adding quickly still produces a VP, and adding in the kitchen yields another VP. This category-preserving pattern creates recursion and requires an operation called adjunction.
V-bar
├── PP adjunct
└── V-bar
├── V-bar
└── PP adjunctBecause each new mother has the same category as its original daughter, the operation can repeat indefinitely. Adjunction is not restricted to V-bar; it also applies to other categories, including modifier structures inside noun phrases.
Why can complements not be added without limit in the same way as modifiers? Which property of a head restricts their number?
Complements are selected by a head and occupy the limited structural positions provided by its elementary tree. Modifiers are unselected and enter recursively through adjunction.
Bringing the Clause Analysis Together
Functional layers and three structure-building operations jointly account for clause form.
A clause cannot be treated adequately as a VP alone. Modals, auxiliaries, negation, subject relations, and embedded-clause markers motivate a sequence of functional projections around VP.
- I contains a modal or tense and projects IP.
- Neg projects NegP between I and VP.
- C projects CP over IP, particularly in embedded clauses.
The VP-internal subject hypothesis places the subject first with the verb that selects it. Movement then raises it to spec-IP, where it can participate in agreement. Idiom patterns and quantifier stranding support this lower origin.
- Substitution inserts selected arguments into complement and specifier positions.
- Movement repositions a phrase through copying or a trace relation.
- Adjunction attaches modifiers through category-preserving recursion.
Together, these operations and functional layers describe simple and embedded clauses containing tense, modals, negation, and multiple modifiers. They also connect word order and agreement to the positions and relations represented in the syntax.
Common misconceptions
Watch out: A modal is simply another verb in a recursive series of VPs.
Instead: Modals form a closed functional category and have only finite forms, so they cannot occur as the non-finite complement required by another modal. They occupy I and select VP or NegP.
Watch out: The surface subject is an argument selected by the modal because it appears before the modal.
Instead: The main verb assigns the subject its thematic role. The subject begins inside VP and moves to spec-IP, where it enters a grammatical relation with inflection.
Watch out: A clause without an overt modal is a VP rather than an IP.
Instead: Modal clauses and simple finite clauses have the same distribution. A simple finite clause is also an IP, with a silent tense head in I.
Watch out: Modifiers should be listed in a head's elementary tree just like selected complements.
Instead: Modifiers are not selected by the head and may occur in nearly unlimited numbers. Adjunction adds them recursively without changing the category of the modified phrase.
Lesson recap
- Clause structure is layered: CP may contain IP, and IP contains VP; NegP can occur between I and VP.
- The subject is selected within VP and moves to spec-IP for a higher grammatical relation such as agreement.
- Idiomatic VP units and floating quantifiers provide evidence for the subject's VP-internal origin.
- Finite clauses without modals still contain I, realized as silent tense that determines the main verb's form.
- Substitution inserts arguments, movement relocates phrases, and adjunction adds recursive modifiers.