Syntactic Tree Generator Syntax Tree Diagrams
Enter any sentence and our AI will create a labeled syntactic tree showing phrase structure, constituency, and hierarchical grammar. Perfect for linguistics courses, syntax homework, and language research.
Syntactic Tree Generator
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Syntactic Tree Examples
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Simple Sentence Parse Tree
Basic constituency parse tree for a simple English sentence, showing noun phrase and verb phrase structure with terminal nodes.
Complex Sentence with Clauses
Parse tree for a complex sentence featuring an embedded subordinate clause with complementizer phrase structure.
Question Formation Tree
Parse tree illustrating wh-movement and subject-auxiliary inversion in English interrogative sentence formation.
Passive Voice Tree
Parse tree for a passive voice sentence demonstrating NP-movement from the complement position to the subject position.
Relative Clause Tree
Parse tree showing a relative clause modifying a noun phrase, with the relative pronoun in Spec-CP and a gap in the embedded clause.
Noun Phrase X-bar Tree
X-bar theoretic structure of a complex noun phrase with specifier, adjunct, and complement, illustrating the three levels of projection.
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What is a Syntactic Tree?
A syntactic tree, also called a parse tree or phrase structure tree, is a diagram that represents the hierarchical grammatical structure of a sentence. Unlike flat sentence diagrams that show word-level relationships on a baseline, syntactic trees display how words group into phrases and how those phrases combine to form larger constituents up to the sentence level. Each node in the tree is labeled with a syntactic category such as S (sentence), NP (noun phrase), VP (verb phrase), or PP (prepositional phrase). Terminal nodes at the bottom of the tree correspond to the actual words in the sentence. Syntactic trees are a foundational tool in theoretical linguistics, computational linguistics, and language education.
Phrase Structure Rules
- S -> NP VP: a sentence consists of a noun phrase followed by a verb phrase
- NP -> (Det) (AdjP) N (PP): a noun phrase optionally contains a determiner, adjective phrase, head noun, and prepositional phrase
- VP -> V (NP) (PP) (AdvP): a verb phrase contains a verb and optional complements such as noun phrases, prepositional phrases, or adverb phrases
- PP -> P NP: a prepositional phrase consists of a preposition followed by a noun phrase
- CP -> (C) IP: a complementizer phrase optionally contains a complementizer followed by an inflectional phrase, used for embedded clauses
- These rewrite rules are called phrase structure rules or context-free grammar rules, and they define the legal structures of a language by specifying how each phrase category can expand into its constituents
How to Draw a Syntactic Tree
To draw a syntactic tree, begin by identifying the sentence and labeling the top node S. Divide the sentence into its major constituents, typically a subject NP and a predicate VP. Continue breaking each phrase into smaller components following phrase structure rules: determiners, adjectives, nouns within NPs; verbs, objects, and prepositional phrases within VPs. Draw branching lines from each parent node down to its children. Terminal nodes hold the actual words of the sentence. Every non-terminal node must be labeled with a syntactic category. Ensure that the tree is binary-branching where possible, reflecting modern syntactic theory. Our AI generator automates this entire process, producing correctly labeled trees from any input sentence.
X-bar Theory Basics
X-bar theory is a component of generative grammar that provides a uniform template for the internal structure of all phrases. Under X-bar theory, every phrase has the same three-level architecture: a head (X), an intermediate projection (X-bar or X'), and a maximal projection (XP). The head is the core lexical item, the X-bar level combines the head with its complement, and the XP level adds a specifier. For example, in a noun phrase, the head N combines with a PP complement to form N-bar, and a determiner specifier combines with N-bar to form the full NP. X-bar theory ensures structural consistency across all phrase types (NP, VP, AP, PP, IP, CP) and is the basis for much of modern syntactic analysis taught in university linguistics courses.
Uses of Syntactic Trees in Linguistics
- Theoretical syntax: testing hypotheses about phrase structure, movement operations, and binding theory using tree representations
- Language teaching: helping linguistics students visualize constituency, headedness, and hierarchical structure in courses on syntax and morphology
- Computational linguistics and NLP: parsing algorithms such as CKY and Earley parsers generate syntactic trees to analyze sentence structure in software applications
- Typological research: comparing the syntactic structures of different languages by contrasting their tree configurations for word order (SVO, SOV, VSO)
- Psycholinguistics: modeling how the human parser incrementally builds syntactic structure during real-time sentence comprehension
- Second language acquisition: diagnosing syntactic transfer errors by comparing L1 and L2 tree structures for corresponding sentence types
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