What is fluency ,Components of fluency ,factors of fluency , and Diadochokinetic rate (DDK)

What is Fluency

• Fluency – derived from Latin word ‘Flure’

• Fluent speaker - some one whose speech is easy and 

that flows from word to word without effort 

• The speech flows easily and smoothly in terms of 

both sound and information

• There are no disruptions of the message and the 

listener can attend to the message 

Stark Weather, 1987

• Fluency: “People who are fluent are so skilled in the 

performance of speech and language behaviors that 

they don't need to put much thought or energy into 

talking.“

• Flow of speech

Fluency

• It refers to speech that flows without hesitation or stoppage 

• Relates to the degree to which syllables and words are logically 

sequenced as well as the presence or absence of pauses 

• If semantic unit follows one another in a continual flow of 

information – Fluent speech

• If units fail to flow in a logical sequence - information does not flow Fluency

Fluency & Disfluency in a continuum

Disfluency  & Fluency

Fluent speech

• Normal speakers- Are they fluent?

• No!

• Few stressful conditions, normal speakers experience 

disruptions in the flow of their words and sounds.

• Why?

• Language and speech production is a complex task 

and requires many years of experience especially 

under stress conditions.

Components of Fluency

• Starkweather (1987) suggests,

• 2 components

• Language and Speech components

Linguistic fluency

➢Syntactic

➢Semantic

➢Phonologic

➢Pragmatic

Dimensions of fluency

➢Speech vs. Language fluency

➢Motoric vs. Linguistic fluency

➢Production vs.Formulation

Linguistic fluency

• Syntactically fluent: able to construct highly complex 

sentences using variety of complex forms. 

• Semantically fluent: 

Speakers are readily able to 

possess large vocabularies.

• Phonologically fluent: 

Speakers are able to 

pronounce long and complicated sequence of sounds 

and syllables. 

• Pragmatically fluent: 

Make timely and appropriate 

verbal responses in a variety of social and cultural 

contexts.

Aspects of speech Fluency

Timing:

• Continuity/Smoothness of speech

• Rate

• Rhythm 

• Duration

Effort: 

• Mental 

• physical

Continuity

Speech is continuous if it flows without 

hesitation/stoppage/disfluencies

• Pauses/hesitations – filled/unfilled pauses

• Unfilled pause- silence

Goldman-Eiler (1968), Clarke (1971)

• Conventional pauses – used for emphasis or linguistic 

purpose

• Idiosyncratic pauses – uncertainty over word choice, 

style or syntax – more common in spontaneous speech, 

longer, complex utterances

Filled pause

• Neutral/meaningless sounds (‘um’, ‘er’, ‘uh’, ‘ah’) 

• Indicates that perception of fluency depends on flow of 

information and not flow of sound

• In speech these serve as a kind of place-holder – a way a 

speaker lets listeners know that he or she has not 

finished speaking 

• PWS use it as a way of easing into fluency or deflecting 

embarrassment when they cannot speak fluently 

Unfilled pauses

• extraneous portions of silence in the ongoing stream 

of speech

• In PWS -usually unintentional and may cause the 

larynx to close, restricting the flow of air necessary 

for speech

• These pauses differ from the pauses that punctuate 

normal speech 

• PWS refer to this as “blocking” 

Continuity

• Pauses more likely before content words (nouns, 

verb)

• Pauses more at clause boundaries (eg., I am going to 

market, to purchase vegetables)

• FP occur before high uncertain words, longer and 

complex sentences

• FP more in the beginning than middle of clauses

• Pauses less in reading than narration or conversation

Measurement of continuity

• Fq. of pauses/hesitations in a known length (no. of 

pauses/total no. of syllables)

• Duration of pauses

•Length of continuous segments/utterances - 6-9 to 

10-50 syllables

• On avg, pause for every 4.8 words in narration, 

7.5 words in discussion 

• Women more fluent than men

Continuity disrupted….

Repetitions

• phoneme- K, K, car

• Syllable- ka, ka, car

• Part word- sent, sent, sentence

• Word: car, car

• Phrase- blue car, blue car

Continuity disrupted….

Prolongations: refers to persistence of phoneme

• Mm…..mango

Continuity disrupted….

parenthetical remarks (interjections)

• Meaningful words

• But not used meaningfully within context

• Eg., I mean, You know, Well…

Continuity disrupted….

• False starts (I am going.., I will be going)

• Different types of grammatical modifications

• Phoneme reversal: coral for colour

• Verb reversal: is going for was going

• Negation: red bus ….. No blue bus. 

Continuity disrupted….

• Broken words (eg., bi si nes)

• Normal rhythm of word is not present

• It interferes with smooth flow of speech

• Eg., I we (pause) nt home.

Continuity disrupted….

• Tense pause

• Event that occur before the first word in a utterance or between 

words

• Indicated by presence of audible manifestations of heavy breathy or 

muscle tension. Disrhythmic phonation: event that may constitute a prolonged sound 

with an accent, or timing.

• An improper stress, break – not compatible with fluent speech

• May or may not involve tension 

Rate

• Refers to the speed in which the words are spoken

• For a speaking task, there is considerable variability in 

rate in terms of such factors as formality of speaking 

situation, time pressure, language, phonetic context 

etc..

• Wide range of acceptable rates in the judgment of 

fluency

• When speaking in a noisy environment – speaker 

slows down (Long Hurst & Siegel, 1973)

• When speaker is producing a lengthy utterance -

more rapid rate (Malecot, Johnson & Kizzear, 1972)• CCV (cry) & CVC (kit) syllables take less time than VCC (ask) syllables

• Syllables that begin with consonants r produced faster than with 

vowels.

Measurements of Rate of speech

➢Diadochokinetic rate

➢Words per minute

➢Syllables per second

➢Duration of individual speech sound.

Diadochokinetic rate (DDK)

• Rate at which articulators move for the production of 

sp sds.

• Instructions: Say /pataka/ as fast as possible

• No. of syllables uttered per second

• Measured using stop watch, spectrogram (spgm), 

software like vaghmi.

• Syllable is identified as peak in spgm

• DDK depends on place of articulation

• Bilabial & velar--- speed of movt is reduced

• WHY?

DDK

• Lips and back of tongue are bulkier

• DDK for /p/ & /k/ is lower than /t/

• Tongue tip is less bulkier

• Avg DDK- 4- 8 syllables/sec

Words per minute (WPM)

• Instructions: to speak or read a passage

• Total No. of words uttered in one minute 

Norms- WPM

Adults

• 160-180 WPM: oral reading task (Calvert & Silverman, 

1983)

• 220-410 WPM: speaking task (Weiner, 1984)

Children (speaking task) – Purcell & Runyan, 1980

• Averaged to 125 WPM: I grade

• Averaged to 142 WPM: V grade

Duration of individual sound

• Each sp sd has duration ---- intrinsic duration

• Also influenced by neighbouring sd---- extrinsic durn

• Several factors affect duration of indvl sp sd.

Klat (1976) classified these factors as, 

✓Extralinguistic

✓Discourse

✓Semantic

✓Syntactic

✓Phonetic

✓Physiological

Extralinguistic

• Speakers' mood and physical condition

Angry: duration Rate : 

Sorrow: Contrast to above

Sick: Rate reduces

• Speaking rate

Fast: duration decrease

Slow: duration increase

• Age

Geriatrics: duration of sp sd is longer becoz of longer 

time to move articulators due to loss of muscular 

elasticity

• Gender

Females speak faster than males

Discourse level factor

• Depends on the use of words

• In general,

• Final word and final syllable is longer.

• Cues for end of phrase and sentence.

Semantic factors

a) Emphasis

contrastive stress: use of stressed and unstressed 

words (duration?)

Eg., Black bird V/s Black bird 

b) Novelty

Unusual word is lengthened compared to familiar word

Syntactic factors

• Phrase lengthening: in phrase final syllable is always 

longer than non final syllables.

• Pre pausal lengthening: syllable or word before pause 

will b longer 

• Final wd lengthening: final syllable of wd is always 

longer than non final syllables.

Phonetic factors

• Intrinsic duration: inherent durn of sd

• Vowels: short /a/ & long /a:/

• Duration of vowel is dependent on tongue height

• /a/ (low tongue ht) is longer than /i/ & /u/ (high)

• For low vowels, velum is low and port is more open 

resulting in longer duration

Phonetic factors--intrinsic

• Among consonants

VL > VD, Aspirated > unaspirated

• Among place/manner of articulation

Bilabials & velars--- longest

Retroflex--- short

Nasals > oral stop

Tap /r/-- short, due to curled tongue position

• Duration of vowels increases when it is stressed

• Vowel duration increases when followed by VD stop 

consonants (/amma/ V/s /appa/)

• Consonant in a cluster is shorter than non cluster 

(/kla/ < /ka/)

Physiological factors

• Bulkiness of articulators

• More bulky: more duration

Eg., bilabials, velars, palatals.

• Less bulky: short duration

Eg., retroflex- tongue tip is involved

Rhythm

• It promotes or enhances fluency 

• Rhythm serves fluency by making it easier for us to 

talk faster 

• Martin, 1972 - “ rhythmic patterning carries a heavy 

information load in ordinary connected speech

Effort

• It refers to the ease with which an act is performed 

• Stark weather (1987) distinguishes 2 types of effort: 

- Physical effort (Muscle movement) 

- Mental effort (Linguistic planning)

Mental effort: encoding process, difficult to measure

PWS:

• Exerts relatively large amount of muscular effort to 

produce the speech

• In addition to the physical effort involved in producing 

speech, the mental effort is usually much greater than 

PWNS

Physical effort

• Refers to action in respy, arty, laryngeal system.

• Stops, Fricatives require more effort than nasals and 

glides (Subtelnyworth & Sakucer, 1966).

• Muscular effort is measured : intra oral air pressure for 

various sp sds

• ME varies with position of sd in a wd, rate, loudness, 

stress and coarticulation.

• Fluent speakers put very little muscular or physical 

effort into the act of speaking

Factors influencing fluency

1. Physiologic:

- Proper strength/tonicity in structures

- Size & mass of the structures

- Coordination between movements

(Stg is a sequencing & timing disorder)

- Perceptual & neural mechanism influencing timing

- Feedback controls

- Motoric demands

- Physical wellbeing

2. Language or linguistic factors 

- Language capacity (oral & reading)

- Syntactic/grammatical complexity

- Content/Function word class

- Utterance length

- Task: Recitation, reading, monologue, dialogue, 

group discussion 

- Mother tongue/other languages

- Confidence in using the language

- Knowledge of the topic

- Linguistic demand

3. Environmental factors:

- Speech model provided

- No. of listeners

- Listeners’ reactions

- Sensitivity to listeners’ reactions

- Demands by the caregivers/teachers – accuracy, speed, 

turn taking, complexity of utterances to be used

- Time pressure to initiate & sustain conversation

4. Other factors:

- Fatigue

- Excessive physical activity

- Psychological reactions – fear, anxiety eg., Speech 

phobia

- Emotions like anger, frustration, grief, excitement

- Personality factors as shyness, withdrawal, 

embarrassment

- Past experiences with fluency failure 

Development of fluency

Capacity for fluent speech comes from

• Increased control over VT movements

• Increased ability to coordinate different movements 

simultaneously

• Increased ability to plan and execute sequence of 

movements

• Increased sense of rhythm

• Language maturity in terms of all aspects

Studies - Children’s speech becomes increasingly 

fluent as they mature

• When children first begin to produce speech to 

convey ideas- produced slowly and rhythm is missing 

• Later they learn to deal with lapses of fluency in more 

sophisticated ways.

Development – Speech Continuity

• Yairi,1981 – From 29 to 33 to 37 mths, discontinuities 

decline from 6.5 % to 5.10% to 4.10% 

• Wexler & Mysak,1982 - decline from 14.6% to 9.1% 

from ages 2-4 but then remain the same from 4-6 yrs

• Dejoy & Gregory,1975 - From 3 ½ - 5 yrs, 

discontinuities decline from 11.9 – 9.5%

• Yairi,1981- In 2 yr olds, repetitions of small units & 

interjections and revision

Development of Rate

• Shows clear developmental trends in pause duartion, 

length of utterance, syllables/sec and segment 

Pause duration:

• Kowal, O’ Connel & Sabins - duration of unfilled 

pauses is an excellent measure of fluency 

development.

• It directly influences the rate of speech

• It shows strong developmental trends that parallel 

another fluency measure of known clinical 

importance – part word repetitions

• It shows a clinically important difference between 

the sexes 

• It is not independent of language fluency

• Long unfilled pauses - extra time to plan language, 

not speech 

• The rate of speech - little different at each of levels 

of organization.

• Most complex level of the utterance

- Rate of utterance is related to the length of 

utterance and amount of information in the 

utterance

In longer utterance - The amount of information in 

each word is less than that in a shorter utterance 

• This is because of the additional redundancy of the 

context i.e. one can supply the missing item more 

readily in a longer utterance

• Johnston et al 1972 - Rate of speech in syllables/sec is 

faster in longer utterance

• The rate can be assessed in word and syllable levels 

also 

Study by Smith,1978 

• Compared the duration of 9 words in the speech in 2 and 

4 year children with that of adults 

• The speech of children gets faster and faster with age 

2 yrs

Development of speech rhythm

• 18-36 months lacks normal rhythm - unable to imitate 

sentences (Eilers, 1975)

• In 2 yrs (Hawkins et al,1980) - speech rhythm has 

fewer syllables per foot & so it sounds more syllable 

timed

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

environments,

- word initial

- next to unstressed syllable (Hawkin, 1979)

• 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 F0 of the 

stressed syllable 

• Sounds in the unstressed syllable may be lost, and 

instead the child produces adjacent, stress syllable 

(“ray-ray for raisin”)

Development of ease in speech

• No direct measures of the effort in the production of speech

• Thought is required before an utterance to plan its execution but 

once this planning is accomplished the utterance is executed 

automatically

• Planning time decreases as the child develops 

Length of unfilled pauses shortens as the child grows

• Rate of speech increases as the children grow

• Children acquire the abilty to talk with less muscular 

effort

.