1Psych 56L/ Ling 51:Acquisition of LanguageLecture 10Lexical Development IIAnnouncementsReview questions for lexical development availableHomework 2 assigned today 11/5/08, due 11/12/08 in classPlease pick up midterm and homework 1 if you haven’talreadyFinding the Words“Look! There’s a goblin!”Goblin? Agoblin?Speech isn’t neatly dividedLooktheresagoblin! = Look! There’s a goblin!Word segmentation: process of dividing a stream of speech intothe units that adults attach meaning to - wordslUkDE®z´gablIn = lUk DE®z ´ gablIn2Word segmentation is hardFather: Who wants some mango for dessert?s´m meNgoChild: What’s a semmango? s´mmeNgoExamples of real errors that children make:Word segmentation is hardExamples of real errors that children make:“…and to the flag of the United States…” yunajt´d stets“…and to the flag of the nine of states…” najn ´v stetsPledge of allegiance renditions:“…and to the republic for which it stands…” wItS It stQndz“…and to the republic for witches stands…” witS´z stQndzWord segmentation is hardExamples of real errors that children make:“the answer, my friend, is blowin’ in the wind.” Qns´® maj f®End iz“the ants are my friends, they’re blowin’ in the wind.” Qns a® maj f®Endz DE®Attempting Bob Dylan lyricsSome clues children use to solve itWords recur in the sound stream - children can pick up on theregularities in the sound sequencesFrom Pirate’s Treasure, written by Carol Moore"Ten steps from the porch and twenty steps from the rosebushes," growled Bluebeard in Jimmy's dream one night."There be treasure there! Aawrgh."3Some clues children use to solve itThe stress patterns (rhythm) of the language can also givechildren clues about where words start and end.From Pirate’s Treasure, written by Carol Moore"TEN STEPS from the PORCH and TWENty STEPS from the ROSEBUshes," GROWLED BLUEBEARD in JImmy's DREAM ONENIGHT. "THERE BE TREAsure THERE! AAWRGH."Some clues children use to solve itMotherese - with its exaggerated pitch, longer pauses, and shorterphrases - may help.Figuring out the referent of a word“Look! There’s a goblin!”Goblin = ????The Mapping ProblemEven if something is explicitly labeled in the input (“Look! There’sa goblin!”), how does the child know what specifically that wordrefers to? (Is it the head? The feet? The staff? Thecombination of eyes and hands? Attached goblin parts?…)Quine (1960): An infinite number of hypotheses about wordmeaning are possible given the input the child has. That is, theinput underspecifies the word’s meaning.So how do children figure it out? Obviously, they do….4One solution: fast mappingChildren begin by making an initial fast mapping between a newword they hear and its likely meaning. They guess, and thenmodify the guess as more input comes in.Experimental evidence of fast mapping(Dollaghan 1985, Mervis & Bertrand 1994)ballbearkitty[unknown]One solution: fast mappingChildren begin by making an initial fast mapping between a newword they hear and its likely meaning. They guess, and thenmodify the guess as more input comes in.Experimental evidence of fast mapping(Dollaghan 1985, Mervis & Bertrand 1994)ballbearkitty[unknown]“Can I have the ball?”One solution: fast mappingChildren begin by making an initial fast mapping between a newword they hear and its likely meaning. They guess, and thenmodify the guess as more input comes in.Experimental evidence of fast mapping(Dollaghan 1985, Mervis & Bertrand 1994)ballbearkitty[unknown]“Can I have the zib?”20 monthsKnowing what to guessLexical constraintsWhole-object assumption: new words refers to entire object,rather than some subset of itGoblin =5Knowing what to guessLexical constraintsMutual-exclusivity assumption: assume new word does notoverlap in meaning with known word (can be used toovercome whole-object assumption)Handle = some part of the cupKnown: cup“Look! You can see the handle!”Knowing what to guessLexical constraintsMutual-exclusivity assumption: assume new word does notoverlap in meaning with known word (can be used toovercome whole-object assumption)…not without its ownproblemsSiamese = ????Known: kitty“Look at the kitty! He’s a siamese!”Knowing what to guessSocial CuesSpeakers will look at novel thing they’re talking about: assumenew word refers to object of speaker’s gaze (children do thisby 18 months)Siamese = ????Known as “kitty”“Look at the siamese!”Knowing what to guessSocial CuesSpeakers will look at novel thing they’re talking about: assumenew word refers to object of speaker’s gaze (children do thisby 18 months)Siamese = ????Known as “kitty”“Look at the siamese!”6Knowing what to guessSocial CuesSpeakers will look at novel thing they’re talking about: assumenew word refers to object of speaker’s gaze (children do thisby 18 months)Siamese = ????Known as “kitty”“Look at the siamese!”Knowing what to guessSocial CuesSpeakers will look at novel thing they’re talking about: assumenew word refers to object of speaker’s gaze (children do thisby 18 months)Siamese = Known as “kitty”“Look at the siamese!”Knowing what to guessClues from the inputSpeakers generally talk to children about the here and now(Quine’s problem is not nearly so serious in child-directedspeech)“Look at the siamese!”(Not “I just took her to the vetyesterday. Poor thing’s beensick all of last week.”)Knowing what to guessClues from the inputSpeakers also sometimes provide explicit correction formeaning, and provide additional information about the word’smeaning.“Can I see the bugs again?”“Those are goblins, honey,not bugs. Goblins live inthe Labyrinth andoccasionally take naughtychildren away.”7Knowing what to guessClues from the syntactic structureDifferent grammatical categories (nouns, verb, etc.) tend tohave different meanings. Once children have identified somegrammatical categories (after ~18 months), they can use thesyntactic structure (how words appear together) as a clue tomeaning.“Those are goblins.”goblins = nounNouns = objectsGoblins =Knowing what to guessClues from the syntactic structureExperimental evidence with 4 yr olds (Gelman & Markman 1985)“Find the fep one.”Knowing what to guessClues from the syntactic structureExperimental evidence with 4 yr olds (Gelman & Markman 1985)“Find the fep one.”the__ one = adjectiveadjective = property (like