Rhythm of speech

RHYTHM

Two ways of defining Temporal characteristics of a spoken utterance.,

1)Tempo 2) RhythmTempo is the rate at c utterance is spoken.Rhythm of an utterance is the pattern of time

intervals c elapse b/w occurrences of stressed syllables.

The term ‘Rhythm ‘is derived from the Greek word ‘Rhuthmos’ where ‘Rhu’means flow.

Rhythm is defined as a pattern of movement C occurs on more or less with temporal regularity.

It is a certain swing or balance in bodily movt, Music, verb or phrase.

In Sanskrit literature, ‘Rhythm’ is a nature of time. It means metrical movts. (eg., clock)

• Unit /ta:la/ is measure for rhythm.• Music has regular rhythm- Music has a regular rhythm, - Eg., 1) sa, ri, ga, ma, pa,da, ni, sa 2) Ba, Ba, Black ship

SPEECH RHYTHM

Some rhythm exist in Sp, but not regularRhythm gives a shape to a sentence, an idea of

length of a sentence & Melody. It also marks the beginning and end of a Phrase. It helps in memorizing a particular prose Or poetry

and leads to ease of pronunciation.• Fairbanks (1945): Rhythm is sp pattern of vocal

change which is inherent in sp or draws attention to the need for breathing pattern which underlies pause, stress, rate, pitch & intensity.

Speech rhythm…. CONTDRhythm in Sp is special in 2 ways. Firstly, it is not strictly regular beatTempo & rhythm changes during utterances in

relation to wd & clause boundaries.If there is no rhythm, Sp breaks down leading to

‘dysprosodia’. The sense of rhythm is not properly developed or

is disrupted in HI,STTG,CLTTG dysarthria, apraxia and aphasia {Stark weather, 1987}

.

Measure of rhythm• Feet: a measure of rhythm, distance b/n

successive stressed syllable. • Metrical feet: rhythmic structure of poetry &

suggests that systematic relationship b/n ft & rhythm persists.

• 1 syllable foot: 1 foot (stress on all syllables)• 2 syllable foot: 2 foot• Foot: includes syllable/ single wrd/ diff wrds.

Functions of rhythm Rhythm tends to promote / enhance fluency Rhythm assists in rapid sp prodnAids to anticipate up coming movts.Important perceptual cue for the recognition of

meaningful stimulus.The movement of the listeners tend to be in

synchrony with syllabic rhythm of sp produced by speaker.

Rhythmic patternsClassified as.,1)fast 2)SlowFast rhythm: we hear it as a whole. A machine

gun is a fast sd, we can hardly count its beat. Slow rhythm: we can hear each beat separately.Eg., hand clapping for music.

Types of rhythm in language

If a lang has simple syllabic structure, for eg, VC(eg., at), or CCV (eg., cry) the durational difference b/n syllabic structures is not wide.

duration of syllabic structure--- < 330msunder these circumstances, we use a fast syllable

timed rhythm.If the syllable is still simpler, for eg., VC or CV

then the durational diff b/n syllables is negligible. ------ such lang is mora-timed lang

If a lang has complex syllabic structure, for eg, V & CCCVCC the durational difference b/n syllabic structures is very wide.

For eg., duration of V (eg., I)--- 60 ms, duration of CCCVCCC (eg., strength) is >600ms.

under these circumstances, we use a slow stress timed rhythm.

The rhythm class hypothesis states that each lang belongs to one of the prototypical Rhythm.

Ramus, Nespor & Mehler(1999) measured consonant & vowel intervals in 8 languages(England, Dutch, French, Polish, Spanish, Italian, Catalan, Japanese).

Results: Percentage of vowels & consonants provided

best acoustic correlates of rhythm. Vocalic Intervals (VI) was smaller and

consonant intervals (CI)was greater in English compared to other languages.

This reflected that English has more complex syllable options.

On the basis of VI,CI ,classifies England, Dutch, Polish,

________ stress timed language.

French, Spanish, Italian, Catalan ________ syllable timed language

Japanese ________ Mora timed language.

Eg, occurrence of syllables English Unifom ------- VCVCVCButiful --------- CVCVCVC BUK --------- CVC

KannadaPustaka------- CVCCVCVNanu----- CVCV

English V/s KannadaEnglish: has word final consonantsKannada: word has to end in a vowel.

The type of syllables in English r more complicated than in Kannada.

Consonant Interval is higher in English compared to Kannada.

Pair wise variability Index (PVI)Grabe and Low (2002) calculated PVI across

languages.PVI : calculation of successive vocalic and

intervocalic interval pattern. Based on PVI., England, Dutch, Germany – as stress timed

languageFrench, Spanish - as syllable timed language

Japanese - as mora timed language

Inter vocalic interval (IVI) vocalic interval(VI-vowel duration) IVI VI Stress timed language High High Syllable language High Low Mora language Low Low

Measurement of rhythm--- productionRecord sp sample tap for rhythm indicate the taps on a transcribed materials. Sp samples of Normals can be compared with that

of clinical population for production of rhythm. Acoustically , measure Fo, duration, intensity of the

tapped syllable. Acoustic measures in clinical popn can be

compared to that of normals.Pair wise variability index can b measured.

Measurement of rhythm--- speech perceptionRhythm can be simulated or recorded music can be

playedParticipant r instructed to tap for the rhythm heard.Acoustically analyzed for correct perception of

ta:la, duration b/n taps and reaction time. Same procedure can be used for training to

perceive Rhythm by providing the visual cues of tap by

clinicianhigh lighting auditorily change in rhythmic pattern.

Indian studies

Savithri, Jayram, kedaranth & Goswami (2006) investigated rhythm in Hindi & Kannada

language Reading and spoken lg was recorded and

analyzed for PVI.Results: Hindi ----syllable timed language Kannada----- mora timed language.

To summarize concepts on rhythm measurement,

initially concept of Isochrony (syll hs equal duration) was noted

Followed by vowel duration, % vocalic & consonant intervals.

Finally PVI usedhowever there r still unclassified lgs . Therefore

there might b much more than PVI.

Indian studies• Balasubramaniam (1980)• Rhythm in tamil lang• Results: Tamil is neither a stress timed nor a

syllable timed lang• Why not stress timed lang?• Stressed syllable do not tend to occur at

regular intervals of time• Why tamil is not syllable timed lang?• Syllables do not occur at regular intervals of

time

Indian studies

• What is Stress timed lang? it takes one unit of time to utter 1 unstressed

syllable b/n 2 successive stressed syllables, 3/4/5 unstressed syllable b/n 2 successive

stressed syllables, • Should take the same unit of time• Stress is not present as above in tamil lg,

hence its not a stress timed lg.

Indian stu• Savithri (1991)• Rhythm in Kannada• Results: 2 feet occurred maximally followed

by 3 feet & 1 foot.• Stress after 2 syllables.

• Eg., ˈnanu ˈi:ga barˈti:ni

• Savithri & Rashmi (1992)• Rhythm pattern in Kannada• Stimuli: 65 Kannada sentences depicting various

emotions– audio recorded• Beats were identified by Kannada spkrs on the

basis of stress patterns.• Results: no specific rhythmic pattern in Kannada,

& no foot pattern. Of all positions final position were maximally stressed.

• Martin (1984): Syllable/ stress timing is a vague notion & rhythm prones to be a misnomer.

Development of Rhythm

Several authors suggested tat rhythm of very young children is syllable timed.

polysyllabic utterances of young child are compared of reduplicated forms ( eg., pumjum for pyjamas)

It includes short sequences of phonologically similar and unreduced monosyllables.

By the age of 4 or 5 the rhythm becomes more adult like.

Atkinson & King (1973)Several studies indicate that the segmental

timing shows a devtl trend in children and that children start to develop Sp rhythm as early as 15 months, C is continuous till age of 12 years.

• 18-36 months - lacks normal rhythm - unable to imitate sentences (Eilers, 1975)

• By 2 yrs (Hawkins et al,1980) - speech rhythm has fewer syllables per foot & so it sounds more syllable timed since early utterances r composed of largely reduplication of syllables.

• Syllables are deleted by 2-3 yr olds in 2 phonetic environments,

- word initial - next to unstressed syllable (Hawkins, 1979)4-7 yrs, followed after 14 mnths, found durational

devtl trends were evident as age ↑.

• The very 1st word children produce do not show as much stress contrast as in adult speech (Ingram et al,1974)

• 2 syllable word containing stressed and unstressed syllable are typically produced as if they were spondees

• The only indication of stress is in the raised Fo of the stressed syllable

• Sounds in the unstressed syllable may be lost, and instead the child produces adjacent, stress syllable (“ray-ray for raisin”)

Dissimoni(1974)• Avg duration of vowels & consonants↓ as age ↑• Suggests child’s accuracy & ability to control

timing of sp improves with age.• Yairi (1981): children start acquiring sp rhythm by

the age of 2-3 yrs & then it develops upto age of 8 yrs.

Models of Rhythm: Three models

1.Comb model (Kozhevnikov & Chistovich, 1965)2.Chain Model (Kozhevnikov & Chistovich, 1965)3.Isochrony Model (Abercrombie, 1965)

Comb Model

- According to this model, the units of sp are executed according to some underlying

Programmed time schedule.- Pre programming is similar to open-loop control

B1, B2, B3 ---- phonemes

B1

B2 B3

- the control exercised in the system, does not rely on the o/p (feedback).

- Preprogramming may also be defined as a set of commands that are structured

Before a movement sequence begins and that allows the entire sequence to be

Carried out, uninfluenced by peripheral fd back (Keele, 1968)

Chain Model

there is no underlying time program or rhythm.-A given SP gesture, simply is executed after the

preceeding gestures have been Completed successfully.

B1

B1

B2

B2

B3

B3

- A chaining strategy for motor sequencing assumes that the performance of any

of a series of movements depend, upon fd back, regarding the accomplishment of

a preceding movement.

Isochrony Model

• ‘Isochrony’ refers to the phenomenon. • In a stressed timed language Ex: English,

Stressed syllables follow each other at approximately equal time intervals.

• In the isochronous foot model, the first syllable in each foot is a stressed syllable,

• If the model is correct, the durn of every foot will be equal.

• The rhythm of an utterance is the pattern of time intervals which elapse b/n the Occurrence of stressed syllables.

Two Types of rhythmic patterns are found in isochrony.

1.Stress timed isochrony2.Syllable timed isochronyIn stress timed lg the stressed syllables follow

each other at approximately equal time intervals

Eg: S1’ S2 S3 S4’ S5 S6 Eg., English T1 T2 If, T1 = T2, (T=Time) = 500 ms, (S=Syllable)Stress will occur for every 500 ms

In syllable timed languages, the syllables follow each other at regular time intervals, Eg: French .,Eg: S1’, S2, S3’, S4, S5’, S6,

concept of foot in rhythm1 Foot - stress occurs on all syllables - S1’, S2’, S3’,

S4’2 Foot - Stress occurs on alternate syll - S1’, S2, S3’,

S43 Foot - Every 3rd syll is stressed - S1’, S2, S3, S4’, S5,

S6,S7’4 Foot - Every 4th syll is stressed - S1’, S2, S3, S4, S5’,

S6, S7,S8

5 Foot -Every 5th syll is stressed - S1’, S2, S3, S4, S5, S6’, S7,S8,S9, s10

6 Foot –Every 6th syll is stressed - S1’, S2, S3, S4, S5, S6, S7’,S8,S9, S10, S11, S12

In Sp it occurs up to 6 feet & occurrence of 7-12 feet is very rare.

Tests of RhythmThe Tennessee test of rhythm and inton

patterns (T-trip) Developed by Koike & Asp (1981). 3 parts, 1-17 Test items, Part 1 & 2 : tests for rhythm, part 3 : test for

intonationNonsense syllable / ma/ spoken & recorded with

different rhythm and inton patterns.

- Musical notations were used to indicate the appropriate tempo.

- The rhythmical patterns had 2 levels of stress (stressed or unstressed) & two levels of tempo (regular or quick) for each syllable.

- Since stressed syllable usually have a higher pitch, the stressed syllable was designated as high pitch (top line) & unstressed syllable as mid pitch (mid line)

- Each syllable was identified by a single dot (large dot- stressed, small dot- unstressed)

For part I, the rhythm section – Test items 1-14, had 2-6 syllables(/ma/) varied in stress and tempo.

In Part II:- Items 15,16 & 17 The tempo ed 1-3 syllables / beat & this

produced 3-9 syllables . - children (3 years & 5 years) imitated the pattern - Results: 5 years old scored significantly better

than 3 years old. - The T-Trip test appears to be sensitive to

differentiate b/n grps of different ages.

-

Figures depict the rhythm part of the T-Trip test.1 7

Big dot: stressed, small dot: unstressed, top line: high pitch, mid line: mid pitch, baseline: lowRegular, quick, pause----- pattern

Synthetic test of rhythm (Jayanthi Ray, 1993)17 synthetic stimuli varying in Fo, intensity and

duration. Part 1, 2 & 3In part 1, 6 stimuli with change in Fo ( increase in

steps of 10 hz) keeping intensity and duration as constant were prepared.

In part 2, 6 stimuli with change in intensity (in steps of 10 dB steps) keeping fq and duration as constant.

In part 3, 5 stimuli with change in duration ( in 10 ms steps) keeping fq and intensity as constant.

Synthetic test of rhythm….. contd• These stimuli were given for imitation by

adults and children. • Results indicated,Adults cud imitate 1 ft to 4 feet, had difficulty

in imitating 5 ft & 6 ft.Stimuli with intensity & Fo changes

(individually) were better imitated than duration.

Devtl trend ws indicated in children

Synthetic test of rhythm……contd

• This test can b used as clinical tool to explore suprasegmental functioning in persons with dysprosodia.

• Therapeutic tool to facilitate rhythmic sp• To enhance sp intelligibility in persons with

arhythmia.

Rhythm in Normals

The discontinuity in Normal speakers r likely to occur at syntactic location where lang is

being formulated.

Rhythm in sttg

• Starkweather & Gordon (1983): Sttg & other discontinuities r likely to occur at syntactic locations were lang is being formulated.

• Physiological weakness of coordination in spkg• Results in as lack of fluency--- slow rate, repeated

elements, hesitation, unusual amt of effort in spkg.

• Hence, disfluency is a sign of temporal incoordination.

Implications to TxWith additional information on rhythm, focus

on rhythm is possible.For eg., if a language is stress timed, a stress

timed approach to teach rhythm is appropriate. If a language is mora timed, then a mora timed

approach is appropriate Prolonged sp techniques r based on the idea of

equal syllable timing.If a language is stressed timed language,

prolonged sp techniques may not be appropriate.