Resources · Linguistics tool
Syntax Tree Generator
Type an English sentence to see its phrase structure tree. If the sentence can be read in more than one way, you'll see every reading.
Trees use basic phrase structure. Different textbooks draw some structures differently, so here are the conventions this tool follows.
S → NP (Aux) (Neg) VP. The first auxiliary sits under S; any further auxiliaries head their own VP: might [have [left]].
As the main verb (is happy), be is V. Before a verb (is reading, was written), it is Aux.
Clauses introduced by that, whether, because, when… are CP → C S. Wh-questions and relative clauses are also CPs.
to is labeled Inf: [VP [Inf to] [VP leave]]. Gerunds are VPs inside an NP when they are subjects.
Particles are labeled Part: gave [Part up], turn [Part off] the lights.
Traces, empty categories, and X-bar levels (N′, V′) are not drawn. Punctuation is ignored.
Labels
- S
- sentence / clause
- NP
- noun phrase
- VP
- verb phrase
- PP
- prepositional phrase
- AdjP
- adjective phrase
- AdvP
- adverb phrase
- CP
- complementizer phrase
- Det
- determiner
- N
- noun
- Pro
- pronoun
- V
- verb
- Aux
- auxiliary / modal
- Adj
- adjective
- Adv
- adverb
- P
- preposition
- C
- complementizer
- Conj
- conjunction
- Deg
- degree word (very)
- Num
- number
- Neg
- negation
- Inf
- infinitive to
- Part
- particle
- Poss
- possessive 's
The trees are generated automatically, so always check them. The tool was tested against 233 hand-checked trees of sentences like those in introductory linguistics and grammar courses. On test sentences it had not seen before, it produced exactly the right tree (and every reading for ambiguous sentences) about 95% of the time.
It is most reliable for short and medium-length sentences. Long sentences with many phrases are more likely to contain a mistake, most often in where a prepositional phrase attaches (workshop on writing vs. attended … on Monday). If a tree is wrong, choose Edit tree and fix the brackets.
Word information: WordNet 3.0, © 2006 Princeton University, used under the WordNet license.