Background: the production of sound for speech Adam Albright - - PowerPoint PPT Presentation

Background: the production of sound for speech

Adam Albright (albright@mit.edu)

LSA 2017 Phonology University of Kentucky

How do humans use sound to communicate?

▶ Speech production

▶ Intended meaning, calculate syntactic form, determine

phonological form, translate into physical instructions ▶ Speech perception

▶ Sound waves enter ear, auditory analysis, parse for linguistically

significant units, determine phonological and syntactic form, reconstruct intended meaning

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Properties of speech sounds

What makes a speech sound speech?

▶ Speech is noise created by air flowing from the lungs, modified as

it exits through the mouth/nose

▶ Speech is just one of many modes of linguistic communication

▶ Hand signs, writing, semaphore, morse code, … ▶ But all except sign language are derivative from spoken speech

▶ Speech is continuous

▶ A fluid stream of sounds, without necessarily any pauses between

individual sounds, words, or even sentences ▶ Speech is segmentable

▶ Composed of smaller units: words, morphemes, syllables, and

individual sounds

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Speech: continuous, yet segmentable

▷

“If you can’t see that, then I don’t know if I can explain it to you”

explain e k s p l ai n Although it’s not obvious from the waveform, the speech stream is composed of smaller units, which we can refer to discretely Phrases, words, phones ( individual speech sounds)

The nature of speech The production of voicing Vowels Consonants 3/54

Speech: continuous, yet segmentable

▷

“If you can’t see that, then I don’t know if I can explain it to you”

explain e k s p l ai n Although it’s not obvious from the waveform, the speech stream is composed of smaller units, which we can refer to discretely Phrases, words, phones ( individual speech sounds)

The nature of speech The production of voicing Vowels Consonants 3/54

Speech: continuous, yet segmentable

▷

“If you can’t see that, then I don’t know if I can explain it to you” ▶ explain = e k s p l ai n

Although it’s not obvious from the waveform, the speech stream is composed of smaller units, which we can refer to discretely Phrases, words, phones ( individual speech sounds)

The nature of speech The production of voicing Vowels Consonants 3/54

Speech: continuous, yet segmentable

▷

“If you can’t see that, then I don’t know if I can explain it to you” ▶ explain = e k s p l ai n

Although it’s not obvious from the waveform, the speech stream is composed of smaller units, which we can refer to discretely

▶ Phrases, words, phones (= individual speech sounds)

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Evidence for discrete phones

▶ Phonemic awareness tasks (typically used for testing

development in children)

▶ What is the first sound in cat? ▶ Which of these words start with the same sound: cat, pat, coat ▶ Say cat without the [k]; say stand without the [t] ▶ Say cat. What word do you get if you change the [k] to [m]?

▶ Language games

▶ pig latin → ig-pay atin-lay

▶ Speech errors

▶ “cad you rean the small print?” ▶ (More common: ‘spoonerisms’ of word-initial consonants)

▶ Alphabetic writing

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Producing speech

T wo components:

▶ Aerodynamic component

▶ Air is forced out of lungs, though throat, mouth, and nose

▶ Articulatory component

▶ Air stream is modified in various ways on its way out

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The vocal tract

nasal passages larynx (glottis) lips teeth alveolar ridge palate velum uvula tongue blade tongue dorsum tongue to the lungs brain

(my vocal tract, for illustrative purposes)

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The vocal tract

The first linguistically significant airstream obstruction: The larynx ( the glottis) From http://www.oto-hns.northwestern.edu/Voice/education.html (broken link)

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The vocal tract

The first linguistically significant airstream obstruction:

☞

The larynx (= the glottis) From http://www.oto-hns.northwestern.edu/Voice/education.html (broken link)

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Manipulations of the vocal folds

Vocal folds are held at varying degrees of stiffness/closure

▶ Completely open: for respiration (= breathing) ▶ Close enough to obstruct airflow: whispering, sighing, [h]

(aspiration)

▶ Close together, intermediate stiffness: normal (modal) voice ▶ Tightly closed: glottal stop (as in [ʔ]uh-[ʔ]oh)

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Voicing

▶ When the vocal folds are held somewhat close together, and with

the right amount of stiffness, air rushing through causes them to “vibrate”

▶ Vocal folds are forced apart and rapidly close again, repeatedly ▶ Periodic vibrations = voicing

▶ Can feel externally as a “buzzing” on your throat; try

[sssszzzzsssszzz]

Voicing is the first major source of noise for speech Creates a complex periodic wave, which resonates in the mouth and nose, and is otherwise modified on its way into the atmosphere

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Voicing

▶ When the vocal folds are held somewhat close together, and with

the right amount of stiffness, air rushing through causes them to “vibrate”

▶ Vocal folds are forced apart and rapidly close again, repeatedly ▶ Periodic vibrations = voicing

▶ Can feel externally as a “buzzing” on your throat; try

[sssszzzzsssszzz]

Voicing is the first major source of noise for speech

▶ Creates a complex periodic wave, which resonates in the mouth

and nose, and is otherwise modified on its way into the atmosphere

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Source properties: voice quality

How would you characterize the difference between these pairs of sounds?

▶ Mpi (Tibeto-Burman, spoken by ≈ 900 people in Thailand)

T

• ne

Word Gloss Word Gloss Low rising

▷

si ‘to be putrid’

▷

si ‘to be dried up’ Low level

▷

si ‘blood’

▷

si ‘seven’ Mid rising

▷

si ‘to roll rope’

▷

si ‘to smoke’ Mid level

▷

si (a color)

▷

si (classifier) High falling

▷

si ‘to die’

▷

si (name) High level

▷

si ‘four’

▷

si (name)

▶ Regular vs. ‘tense’ voice

Hear them here.

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Source properties: voice quality

!Xóõ (Khoisan, Botswana/Namibia) Plain (voiced) Pharyngealized Strident Breathy

▷

kǁáa

▷

qáʕa

▷

k!ào

▷

k!a̤o ‘camelthorn tree’ ‘long ago’ ‘base’ ‘slope’

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Source properties: voice quality

Voice quality contrasts

▶ Bai (Tibeto-Burman, China) (Esling 2002)

▷

tɕi31 ‘field’

▷

tɕi21 ‘flag’ (breathy) (harsh)

▶ English: what determines the voice quality that a word is spoken

with?

Emotive use: frustration, surprise, etc. Individual style: Louis Armstrong, Julie Kavner, etc.

description

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Source properties: voice quality

Voice quality contrasts

▶ Bai (Tibeto-Burman, China) (Esling 2002)

▷

tɕi31 ‘field’

▷

tɕi21 ‘flag’ (breathy) (harsh)

▶ English: what determines the voice quality that a word is spoken

with?

▶ Emotive use: frustration, surprise, etc. ▶ Individual style: Louis Armstrong, Julie Kavner, etc. ▷

description

The nature of speech The production of voicing Vowels Consonants 12/54

The vocal tract as filter

nasal passages larynx (glottis) lips teeth alveolar ridge palate velum uvula tongue blade tongue dorsum tongue to the lungs brain

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The simplest effect

The vocal tract as a tube, closed at one end From: Ladefoged (1996) Elements of Acoustic Phonetics, p. 117

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Resonances

▶ Formants:

Fn = 2n − 1

4 ×

c L

▶ Fn = formant n ▶ c = speed of sound ≈ 35000cm/sec in warm moist air ▶ L = length of the tube

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Calculating tube length

▶ Solving for L

L = 2n − 1

4 ×

c Fn

▶ Example: F1 = 500Hz, F2 = 1500Hz, F3 = 2500Hz

▶ L = 17.5cm

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Possible filtering actions

▶ Can change the size and shape of the oral cavity ▶ Can obstruct the flow of air so much that it must flow through a

very narrow passageway

▶ Can completely block airflow through the mouth ▶ Can open or close velum to allow allow air to flow through nose

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Examining speech sounds

▶ Examining acoustic properties of speech

▶ Praat: http://www.praat.org ▶ Useful for isolating/replaying sounds, and examining acoustic

properties

▶ Waveform vs. spectrogram ▶ Periodic (voicing) vs. aperiod (frication/aspiration) ▶ Both together: [z], [a̤] ▶ Formants

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The simplest filtering action

▶ Vocal tract acts as resonance chamber ▶ T

• ngue acts to control the size of the chamber, and divide into

sub-chambers

▶ Changing size of these chambers alters the sound wave

▶ Boosts amplitude at certain frequencies, dampens others

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What this means, practically speaking

The effect of different tongue positions on the speech signal: Click!

▶ Raising/lowering tongue in different locations results in different

vowel sounds

▶ Height (high, mid, low) and backness (front, central, back)

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A neat demo

Very realistic vowel qualities can be constructed with simple tube models

▶ Exploratorium demo: http: //www.exploratorium.edu/exhibits/vocal_vowels/vocal_vowels.html

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Vowel features

Try this:

▶ Very slowly say the word yeah…, and feel what you are doing ▶ The primary motion is mouth opening/tongue lowering ▶ Along the way, you say a variety of vowels, including:

▶ [i] in heat ▶ [ɛ] in pet ▶ [æ] in cat ▶ (and probably quite a few others…)

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Vowel features

Now try this:

▶ Very slowly say the word how… ▶ Several motions:

▶ T

• ngue body moving back in the mouth

▶ T

• ngue body moving up

▶ T

• ngue “root” (in throat) moving up/become more tense

▶ Mouth closing, lips rounding

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The description of vowels

Vowels can be described along four dimensions:

▶ Backness ▶ Height ▶ T

enseness

▶ Rounding

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Some American English vowels

T ypical American English vowels, in phonetic transcription

(Phonetic transcription indicated with square brackets)

Front Central Back High (tense) i u (lax) ɪ ʊ Mid (tense) eɪ

• ʊ

(lax) ɛ ə, ʌ (ɔ) Low (tense) ɑ (lax) æ Diphthongs: [aɪ] ([aj]) ‘eye’, [aʊ] ([aw]) ‘how’, [ɔɪ] ([ɔj]) ‘boy’ [i] heat [ɪ] hit [u] hoot [ʊ] hook [eɪ] (=[ej]) gate [ɛ] get [oʊ] (=[ow]) goat [ə] attack [ʌ] gut [ɔ]

• ught

[æ] hat [ɑ] father

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Some things to note

☞ Vowel letters (i, e, a, o, u) stand for what are sometimes called

“pure” vowels

▶ Roughly, values used for languages like Spanish, Italian, etc. ▶ These are closest to the English tense vowels, but English vowels

typically also involve an extra off-glide

▶ [eɪ] (= [ej], [e]), and [oʊ] (= [ow], [o])

☞ Special symbols for lax vowels: [ɪ], [ɛ], [æ], [ɔ], [ʊ], [ə], [ʌ]

The nature of speech The production of voicing Vowels Consonants 26/54

A great resource

Demo with sample words, sounds, and animations

▶ http://soundsofspeech.uiowa.edu/english/english.html

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ə and ʌ

▶ [ə], [ʌ] = “neutral vowels” (uh…) ▶ [ʌ] = stressed, [ə] = stressless

▶ abut [əbʌt], amok [əmʌk], Canuck [kənʌk]

▶ Sometimes [ə] is used for both

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ɑ and ɔ

For some American dialects…

▶ [ɑ] = first syllable in father ▶ [ɔ] = walk, caught, all ▶ But many dialects have merged these into an [ɑ]-like vowel

▶ In fact, the U Iowa site mixes together [ɑ] and [ɔ] words, though

the isolated examples are correct

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ɑ and ɔ

For some American dialects…

▶ [ɑ] = first syllable in father ▶ [ɔ] = walk, caught, all ▶ But many dialects have merged these into an [ɑ]-like vowel

▶ In fact, the U Iowa site mixes together [ɑ] and [ɔ] words, though

the isolated examples are correct

The nature of speech The production of voicing Vowels Consonants 29/54

ɑ and ɔ

For some American dialects…

▶ [ɑ] = first syllable in father ▶ [ɔ] = walk, caught, all ▶ But many dialects have merged these into an [ɑ]-like vowel

▶ In fact, the U Iowa site mixes together [ɑ] and [ɔ] words, though

the isolated examples are correct

The nature of speech The production of voicing Vowels Consonants 29/54

ɑ and ɔ

[ɔ]… [a]…

The nature of speech The production of voicing Vowels Consonants 30/54

ɑ and ɔ

[rɔ] [ra]

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Vowel dimensions

Front, central, back

▶ Front = tongue body toward the front of the mouth

▶ [i], [ɪ], [eɪ], [ɛ], [æ]

▶ Central = tongue body neither front nor back

▶ [ə], [ʌ]

▶ Back = tongue body toward the back of the mouth

▶ [u], [ʊ], [oʊ], [ɔ], [a]

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Vowel dimensions

High, mid, low

▶ High: tongue body significantly raised

▶ [i], [ɪ], [u], [ʊ]

▶ Mid: tongue body “neutral”

▶ [eɪ], [ɛ], [ə], [ʌ], [oʊ], [ɔ]

▶ Low: tongue body lowered

▶ [æ], [ɑ]

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Vowel dimensions

T ense, lax:

▶ T

ense: tongue root raised, narrower constriction in back of mouth

▶ [i], [eɪ], [ɑ], [oʊ], [u]

▶ Lax: tongue root lowered/relaxed

▶ [ɪ], [ɛ], [æ], [ɔ], [ʊ], [ə], [ʌ]

The nature of speech The production of voicing Vowels Consonants 34/54

Vowel dimensions

Rounding:

▶ Rounded: lips rounded

▶ [u], [ʊ], [ow], [ɔ]

▶ Unrounded: lips not rounded

▶ In English, everything else…

▶ Some languages have front rounded vowels (German ü, ö; also

French, Swedish, Hungarian, and many others)

▶ The Japanese vowel that is usually written u is actually a back

unrounded vowel

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Vowels: a fuller set

Front Central Back High (tense) i y ɯ u (lax) ɪ ʏ ʊ Mid (tense) e ø ɤ

• (lax)

ɛ ɶ ə, ʌ ɔ Low (tense) a ɑ ɒ (lax) æ

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Rounding and backness

▶ In English, the non-low back vowels are all round ▶ What is the connection between rounding and backness?

“Rounding” lip protrusion

Lengthens vocal tracts Back vowels get ‘backer’

The nature of speech The production of voicing Vowels Consonants 37/54

Rounding and backness

▶ In English, the non-low back vowels are all round ▶ What is the connection between rounding and backness? ▶ “Rounding” = lip protrusion

▶ Lengthens vocal tracts ▶ Back vowels get ‘backer’

The nature of speech The production of voicing Vowels Consonants 37/54

Diphthongs

▶ Vowel and glide combinations

▶ Vowel + glide: aɪ, aʊ, ɔɪ, oʊ, etc. ▶ Glide + vowel: ju, wo, etc.

▶ English: all have glide second

▶ shine, crowd, toy

▶ Spanish: prueba [prweba] ‘test’, viejo [bjexo] ‘old’

The nature of speech The production of voicing Vowels Consonants 38/54

Practice

Describe and give the symbol for the vowels of the following words, as you pronounce them in your speech English: remember to include height, backness, rounding, tenseness

▶ cat, couch, book, feet, neat, lute

(If you are not a native speaker of English, you may want to have a native speaker pronounce them for you.)

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Some useful web resources

▶ IPA chart (including symbols for other languages) https://web.uvic.ca/ling/resources/ipa/charts/IPAlab/IPAlab.htm ▶ Free IPA fonts for your computer http://dejavu-fonts.org/wiki/Main_Page http://sourceforge.net/projects/linuxlibertine/ http: //scripts.sil.org/cms/scripts/page.php?&cat_id=FontDownloadsIPA ▶ T

yping IPA on the web, to copy into another document

http://ipa.typeit.org/ ▶ Drills for describing consonants http://home.cc.umanitoba.ca/∼krussll/phonetics/practice/ consonant/d2intro.htm

The nature of speech The production of voicing Vowels Consonants 40/54

How are consonants different from vowels?

Airflow obstructions

▶ Stopping flow completely ▶ Rerouting through nose ▶ Impeding to varying degrees

Moving tongue, lips, etc., to block air = articulation

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Describing articulation of consonants

Voicing:

▶ Voiced or voiceless

Place of articulation:

▶ Where in the mouth the constriction is created

Manner of articulation:

▶ Degree (and nature) of the constriction

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Place of articulation

nasal passages larynx (glottis) lips teeth alveolar ridge palate velum uvula tongue blade tongue dorsum tongue to the lungs brain

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Place of articulation

Labial (Bilabial) p, b, m (Labiodental) f, v Interdental θ, ð Alveolar t, d, n, l, s, z, Alveopalatal ʃ, ʒ Palatal j Velar k, g, ŋ Uvular (q, ʁ) Glottal ʔ

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Manner of articulation

In increasing amount of obstruction: Stops Obstruents Affricates Fricatives Nasals Sonorants Liquids Glides

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Manner of articulation

In increasing amount of obstruction: Stops Obstruents Affricates Fricatives Nasals Sonorants Liquids Glides

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Manner of articulation

Stops: completely block airflow

▶ Voiceless: [p], [t], [k]

▶ [p] = voiceless bilabial stop

▶ Voiced: [b], [d], [g]

▶ [g] = voiced velar stop

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Aspiration

In English, voiceless stops in some contexts are aspirated

▶ A puff of air after release of closure, and before the beginning of

voicing

▶ Occurs at the beginnings of words

▶ pie [phaɪ], top [thap]

▶ But not after [s]

▶ spy [spaɪ], stop [stap]

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Nasals

▶ It is possible to keep the mouth closed, but open the velum, to

release air through the nose Labial m whim [wɪm] Alveolar n win [wɪn] Velar ŋ wing [wɪŋ] If your nose is blocked, these sounds you can’t make very well; they become the corresponding regular (oral) stops

▶ a stuffy [d]ose

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Fricatives

Flow of air is obstructed, but not completely blocked

▶ Narrow constriction = air escapes quickly and noisily ▶ Characterized by added turbulent noise

Labiodental f, v fan [fæn], van [væn] Interdental θ, ð thin [θɪn], then [ðɛn] Alveolar s, z sin [sɪn], zen [zɛn] Alveopalatal ʃ, ʒ cash [kæʃ], beige [beɪʒ] Velar x Bach [bax]

▶ th in thin = voiceless interdental fricative ▶ th in then = voiced interdental fricative ▶ s in measure = voiced alveopalatal fricative

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Affricates

Air is stopped briefly, but then released slowly, so there is still

• bstruent

▶ Essentially, stop + fricative combinations

Alveopalatal tʃ, dʒ choke [tʃoʊk], joke [dʒoʊk]

▶ ch in church = voiceless alveopalatal affricate ▶ j in judge = voiced alveopalatal affricate

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Stridents

▶ Alveolar and alveopalatal fricatives and affricates are especially

noisy, because they involve very narrow passages for the air to pass through

▶ These are known as stridents, or sibilants ▶ [s], [z], [ʃ], [ʒ], [tʃ], [dʒ]

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Liquids

▶ Relatively less constriction; air escapes freely around tongue ▶ Lateral: [l]

▶ Alveolar constriction, but air escapes around sides of tongue

▶ Rhotic: [r]

▶ T

• ngue curled back or bunched up

▶ Flap: [ɾ]

▶ T

• ngue briefly tapped against alveolar ridge

▶ atom [æɾəm]

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Glides

▶ Consonant versions of [i], [u] ▶ Very similar articulation, but shorter and with narrower

constriction Palatal [j] yes [jɛs] Labiovelar [w] wet [wɛt]

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Consonants

Bilab Lab Inter- Alv Alv- Retr Pal Vel Uvu Phar Glot dent Pal Stop p b t d ʈ ɖ c ɟ k ɡ q ɢ ʔ Fric Non-lat ɸ β f v θ ð s z ʃ ʒ ʂ ʐ ç ʝ x ɣ χ ʁ ħ ʕ h ɦ Lat ɬ ɮ Affric tʃ dʒ Nas m ɱ n ɳ ɲ ŋ ɴ Trill r ʀ T ap/flap ɾ Approx Non-lat ʍ w ɹ̥ ɹ ɻ j (ʍ w) Lat l̥ l

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