Syntax LING October 11, 2006 Joshua Tauberer

Syntax How can the words of a language be put together?

Syntax What makes a valid combination or order of words? What are the relations between the words in a sentence? What is the mechanical system by which we put words together?

Sentence or Word Salad? good students take a linguistics course students linguistics course good a take students good take a course linguistics take students course good linguistics a good students a linguistics course take

Sentence or Word Salad? ✓ good students take a linguistics course * students linguistics course good a take * students good take a course linguistics * take students course good linguistics a * good students a linguistics course take

Sentence or Word Salad? ✓ good students take a linguistics course * students linguistics course good a take * students good take a course linguistics ~ Romance languages * take students course good linguistics a * good students linguistics course a take ~ Japanese, Turkish

Sentence or Word Salad? Sometimes rearranging the words yields word salad. Sometimes rearranging the words gives a different meaning.  John likes Mary.  Mary likes John. Sometimes one arrangement has two meanings  I saw the man with a telescope.  Is this syntax or semantics?

What’s a valid sentence? verb noun verb noun verb noun

What’s a valid sentence? verbLeave! noun verbI ate. noun verb nounStudents like linguistics.

What’s a valid sentence? verbLeave! noun verbI ate. noun verb nounStudents like linguistics. noun verb noun preposition determiner noun Billy sent letters to his mom. noun verb det noun noun verb Sally found the gold I burried. and on...

What’s not a sentence? *noun *noun noun verb verb determiner *noun adjective det det noun adjective verb

What’s a valid sentence? Can we list all valid POS strings?  Is there a longest sentence? Language is unbounded in many ways  coordinationX and Y and Z and...  modifiersin the house on the table...  recursionwho chased the dog that ate the... We need a finite set of rules (the grammar) that gives us an infinite set of strings (the language).

Two Models of Syntax Words as Building Blocks Constituent Structure

Words as Building Blocks A model of syntax: (loosely based on Tree Adjoining Grammar) The mind’s vocabulary comprises a set (lexicon) of special domino-puzzle pieces. noun S verb adj prep verb prep

Words as Building Blocks Assemble the pieces any way so that there are no bumps or holes at the end. Colors must match like dominos. Start with the special S piece. Bill ate S cake read words from left to right (actually “infix order”) the mechanical system

Words as Building Blocks Bill ate S cake some

Words as Building Blocks ate S store the Billcake from

Words as Building Blocks S store the ate Billcake from

Words as Building Blocks S store the ate Billcake from

Words as Building Blocks S cakestore the ate Bill from

Words as Building Blocks Bill S cakestore the ate from

Words as Building Blocks Bill S cakestore the ate from

Words as Building Blocks The way the pieces connect tell us how the words are related. The organization of pieces tells us about the meaning. Bill ate S cake

John likes S Mary Words as Building Blocks The organization of pieces tells us about the meaning. This bump is for the subject. This bump is for the object. Mary likes S John

I S saw a with man a tele- scope How many ways are there two assemble the pieces to make the sentence? with

manI S a tele- scope saw a manI S a tele- scope saw a with Prepositional Phrase Attachment

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order”

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order”

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order”

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a man

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a man

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a man

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a man with

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a man with a

manI S a tele- scope saw a manI S a tele- scope saw a with “Infix Order” I saw a man with a telescope

Garden Path Sentences The horse raced past the barn fell. Grammatical?

Garden Path Sentences More from Wikipedia:  The man who hunts ducks out on weekends.  The cotton clothing is usually made of grows in Mississippi.  The old man the boat.  The player kicked the ball kicked the ball.

Garden Path Sentences horse S the past barn fell the ? raced

Garden Path Sentences horse the past barn fell the raced S

Garden Path Sentences horse S the past barn fell the raced

Garden Path Sentences horse S the past barn fell the raced

Garden Path Sentences horse S the past barn fell the raced

Garden Path Sentences horse S past barn fell the raced The horse (that was) raced past the barn fell. the The yellow ‘raced’ piece is used for relative clauses.

Garden Path Sentences More from Wikipedia:  The man [who hunts] [ducks out on weekends].  The cotton (that) clothing is usually made of grows in Mississippi.  [The old] [man the boat].  The player (that was) kicked the ball kicked the ball.

Constituency and Substitution A second perspective on syntax. Sentences seem to have replaceable parts. Billy ate peaches from the store Billy ate cookies from the store Billy ate the pie from the store Billy ate the pie in the box Billy ate the pie on the box Billy sold the pie on the table the store sold the pie on the table

Constituency and Substitution But parts can’t be replaced with just anything. Billy ate peaches from the store Billy ate sold from the store on the table ate peaches from the store Billy ate peaches the pie Just as words are categorized by part of speech, replaceable parts (“constituents”/ phrases) come in different types.

Constituency and Substitution Billy ate the pie from the store nouns = { pie, cookies, store, table, Billy } verbs = { ate, sold } prepositions = { from, in, on } noun phrases = { cookies, the pie } prepositional phrases = { from the store, in the box, on the table, just until the clock struck seven }

Constituency and Substitution Billy ate the pie from the store nouns = { pie, cookies, store, table, Billy } verbs = { ate, sold } prepositions = { from, in, on } noun phrases = { nouns, det + nouns } prepositional phrases = { preposition + noun phrases } determiner = article (‘the’, ‘a’)

Context Free Grammar Let’s say a sentence (S) is defined by a rule: NounPhrase Verb NounPhrase And a NounPhrase is defined as either:  Noun or  Determiner Noun Keep substituting symbols with other constituents of the same category until only words in the language remain.

Context Free Grammar S NounPhrase Verb NounPhrase Noun ate Determiner Noun Billy ate the cookies

Context Free Grammar S NounPhrase Verb NounPhrase Determiner Noun has Determiner Noun the store has the pie

Context Free Grammar Trees show order symbols were replaced. Also shows the constituent structure.

Context Free Grammar

Recursion Billy eats worms Ruthy made Billy eat worms The teacher let Ruthy make Billy eat worms I saw the teacher let Ruthy make Billy eat worms The principle knows I saw the teacher let Ruthy make Billy eat worms The superintendent wonders whether the principle knows I saw the teacher let Ruthy make Billy eat worms

Recursion S NP Verb S NP let S Det Noun let S the teacher let S the teacher let Noun Verb S the teacher let Ruthy make S the teacher let Ruthy make Noun Verb Noun the teacher let Ruthy make Billy eat worms

Recursion

verb

Recursion

PP Attachment with Trees How is PP-attachment ambiguity represented with trees? Let’s define a Prepositional Phrase first:  S → NP Verb NP  NP → Det Noun  PP → Prep NP Recursively define S’s and NP’s.  S → S PP  NP → NP PP “Any valid S/NP can have a PP tacked on and still be a valid S/NP.”

PP Attachment with Trees