Trees and Constituents Grammars and Lexicons 11-721 Fall, 2003 Phrasal Categories Sentence Verb Phrase Prepositional Phrase Noun Phrase Det Noun Modal Verb Adjective Phrase Noun Phrase Adverb Adjective Prep. Det Noun This boy must seem incredibly stupid to that girl. Phrasal Categories • NP: Noun Phrase • VP: Verb Phrase • PP: Prepositional Phrase • AP: Adjective Phrase • AdvP: Adverb Phrase • S: Sentence Tree Terminology • • • • • • • • • • Mother Daughter Sister Dominate Immediately Dominate Node (branching or non-branching) Branch Terminal Node/Leaf Node Phrasal Nodes (non-terminal) Lexical Nodes (pre-terminal) Constituent • A constituent is a string of words such that there is one node that dominates those words and no other words. S Tree 1 VP PP NP NP N V P Sam climbed Det up the ladder. S Tree 2 VP NP N NP V V Sam picked P up N Det N the ladder. Discussion • What are the constituents of Tree 1 and Tree 2? • Which strings of words are constituents in one tree but not the other? Coordination as a diagnostic test for constituency • To test whether a string of words s1 is a constituent, conjoin it using and with another string which – Is an uncontroversial constituent of the same category as s1 or – (If you don’t have a hypothesis about the category of s1), has the same part of speech sequence as s1 Applying the coordination test • Sam climbed [up the ladder] and [out the window]. • *Sam picked [up a ladder] and [out some new boots]. Movement as a test for constituency • A constituent might appear in different positions in a sentence, but stay in one piece. • There are different movement rules that affect different constituents (NP, PP, AP, VP). Transformational Grammar and Movement Rules S NP S Meaning preserving tree-to-tree mapping NP VP VP The chocolate V The kids V ate NP PP was eaten by the kids the chocolate Surface Structure Deep Structure Transformational Grammar 1. 2. 3. 4. Sentences that mean the same thing have the same deep structure. Tree-to-tree mappings convert deep structure trees into surface structure trees. Tree-to-tree mappings must be meaning preserving, so that (1) remains true. Government and Binding Theory and the Minimalist Program (Chomsky) are theories that characterize which tree-to-tree mappings are meaning preserving. 1. 2. 3. The kids ate the chocolate. The chocolate was eaten by the kids. (meaning preserving) The chocolate ate the kids. (not meaning preserving) Non-Transformational Grammar • In this class, we will not use transformational grammar. • There will be no tree-to-tree mappings. (There will be other kinds of mappings.) • The canonical representation of meaning will not be a deep structure tree. • There will be a different way to connect sentences that mean the same thing. Movement is still a useful metaphor at this stage in the course • • • • Sam climbed up a ladder. Up a ladder Sam climbed up a ladder. Sam likes chocolate. It is chocolate that Sam likes chocolate. To use movement as a test for constituency • First, identify a meaning preserving movement rule (tree-to-tree mapping). • Give an example showing this movement rule applying to an uncontroversial example: – Sam ran into the room. – Into the room Sam ran. Applying the movement test • Then apply the same rule to a controversial example that you want to test. • Sam climbed up a ladder. • Up a ladder Sam climbed. passes the test • Sam Picked up a ladder. • *Up a ladder Sam picked. fails the test Another movement rule • Identify a meaning preserving movement rule and illustrate it with a non-controversial example: – He ran into the room. – It was into the room that he ran. • Apply the movement rule to the controversial examples that you want to test. – – – – He climbed up a ladder. It was up a ladder that he climbed. passes the test He picked up a ladder. *It was up a ladder that he picked. fails the test Be sure that you are testing the right thing • Are these sentences relevant in showing Tree 1 and Tree 2 have different structures? – – – – – – – – It was a ladder that Sam climbed up. It was a ladder that Sam picked up. Sam climbed up a ladder and a wall. Sam picked up a ladder and a rope. ?*A ladder was climbed up by Sam. A ladder was picked up by Sam. A ladder he climbed up. A ladder he picked up. Discussion • Test each sentence with coordination and movement tests for Tree 1 and Tree 2. – – – – – I took out the garbage. I turned off the light. I turned off the highway. I fell off my bike. I looked up the number. Non-Constituent Coordination • John found the letter and Bill signed the letter. • John found the letter and Bill signed the letter. S NP John VP V NP Det N found the letter Non-Constituent Coordination • I gave a book to Mary and gave a letter to Sue. • I gave a book to Mary and gave a letter to Sue. S VP NP V I gave NP a book PP to Mary Right Node Raising • If you conjoin two strings of words that have identical final constituents, delete the first instance of the identical constituent. • John found the letter and Bill signed the letter. Left Peripheral Ellipsis • If you conjoin two strings of words that have identical initial constituents, delete the second instance of the identical constituent. • I gave a book to Mary and gave a letter to Sue.