B.ASLP Semester II: Fluency and its Disorders - Unit 1 & 2 Review

Course Overview

• Course Code: Semester II B2.1

• Subject: Fluency and its Disorders

• Total Hours: 45

• Total Marks: 100 ($80$ marks External + $20$ marks Internal Assessment)

1. Unit 1: Foundations of Fluency

• Etymology: Fluency is derived from the Latin word "fluens," meaning "flowing."

• General Definition (Layman's Terms): Refers to a general proficiency in reading, writing, or speaking.

• Communication Definition: Effortless, rapid flow of utterance.

• Starkweather (1986) Definition: Fluency is an effortless continuous speech at a rapid rate of utterance, regardless of whether it refers to first or second language skills.

2. Dimensions of Fluency

• Continuity:

  • The smooth flow from one sound to another in a syllable, one syllable to another in a word, or sentence to sentence in a paragraph.

  • It refers to the logical sequencing of syllables and the presence or absence of pauses.

• Rate:

  • The speed at which speech moves, signaling the perception of fluency.

  • It is determined by the frequency and duration of pauses.

  • Most speakers talk as fast as they can within their physiological limits.

• Effort:

  • Mental Effort: Refers to encoding and planning processes (sequence of phonemes, duration planning).

  • Physical/Muscular Effort: Relates to the muscular exertion required to provide airflow, manage the glottis, and move articulators (tongue, lips, jaw, velum, pharynx).

3. Language Fluency Types (Fillmore, 1979)

• Syntactic Fluency: The ability to construct highly complex sentences.

• Semantic Fluency: Possession and access to large vocabularies.

• Pragmatic Fluency: Adeptness at verbal responses across various speaking situations.

• Phonologic Fluency (Added by Starkweather): Ability to pronounce long, complicated sequences of sounds, including nonsense and foreign words.

4. Continuity and Pausing

• Clarke (1971) Pauses:

  • Conventional Pauses: Made by competent speakers for emphasis or to signal linguistic importance.

  • Idiosyncratic Pauses: Reflect hesitation or uncertainty over word choice, style, or syntax.

  • Unfilled Pauses: Simple silence lasting longer than a specific interval, typically around $250ms$.

  • Filled Pauses: Utterance of neutral/meaningless sounds such as "um," "uh," "ah," or "er."

  • Hesitations: Unfilled pauses or hard contact of articulators.

• Goldman-Eisler Findings:

  • Unfilled pauses occur on average every $4.8$ words in narrative descriptions.

  • Unfilled pauses occur every $7.5$ words in discussion.

  • Half of continuous speech time is divided into phrases less than three words long.

  • Only 10 ext{%} of speech time is composed of phrases ten words or longer.

• Predictable Distribution:

  • Pauses usually occur before content words (nouns, verbs) rather than function words (prepositions, articles) and tend to occur at clause boundaries.

5. Repetitions (David, 1939)

• Definition: Utterance of a sound, syllable, or word more than once.

• Characteristics:

  • Addition of words like "yes/no" or "hey/too" does not spoil the repetition.

  • Can occur within a repeated sentence (e.g., "Put it in the bag put it put it in the bag").

  • Calling a name repeatedly (e.g., "Johnny, Johnny, Johnny").

  • Absence of articles in rapid speech counts as repetition if corrected (e.g., "Put it in bag, put it in the bag").

• Limitations (Not marked as repetitions):

  • Changing words that alter meaning (e.g., "That’s all I need" vs. "That’s all we need").

  • Changing sentence structure (e.g., "You can’t" to "You cannot").

  • Use of "what?", "mm", or "aa".

  • Pure imitation of sound (e.g., "chuk buk chuk").

6. Dysfluency Classification Schemes

• Yairi (1981) - 8 Categories:

  • Repetitions (sound, syllable, word, phrase).

  • Interjections (extra sounds/words).

  • Revisions (modifying content/grammar).

  • Broken Word (incomplete production, e.g., "I was g…ing").

  • Incomplete Phrase (incomplete thought).

  • Tense Pause (audible heavy breathing/muscular tension).

  • Dysrhythmic Phonation (improper stress/breaks).

• Minife and Cooper (1964):

  • Syllable Insertion: Interjections, revisions, repetitions.

  • Deliberation: Pauses and prolongations.

7. Speech Rate Measurement

• Diadochokinetic (DDK) Rate: Measure of how fast articulators move between places in the vocal tract (e.g., "pataka").

  • Normal range: $4-8 syllables/sec$.

  • Slower for bulkier articulators (lips/back of tongue) vs. tip of tongue.

• Words Per Minute (WPM): Calculation: $ext{WPM} = rac{ ext{Number of words}}{ ext{Total time in seconds}} imes 60$.

  • Normal range: $80-180 wpm$.

• Syllables Per Second (SPS): Adult average: $5-6 sps$.

• Software Tools: PM 100, VISIPITCH, Wavesurfer, Spectrogram, Vaghmi, Dr Speech, PRAAT, Cool Edit.

8. Factors Influencing Duration of Speech Sounds (Klatt, 1976)

• Extra-linguistic: Physical/emotional condition (Angry = faster; Sorrowful = slower).

• Age/Gender: Duration increases with age.

  • Children have smaller vocal tracts (restricted movement); elderly have loss of elasticity.

  • Females may speak faster/more fluently, but differences are often not significant.

• Discourse Level: Final syllables in sentences and final words are longer to signal the end.

• Semantic: Stressed words have longer duration; novel/unfamiliar words are longer.

• Syntactic: Phrase structure lengthening (final syllable in a phrase is longer).

• Phonetic Factors:

  • Low vowels (e.g., /a/) are longer than high vowels (e.g., /i/, /u/).

  • Voiceless consonants are longer than voiced.

  • Nasals are longer than stops due to vocal tract volume.

  • Stressed vowels are longer than unstressed.

  • Consonants in clusters have shorter duration than in CV syllables.

• Physiologic: Bulky articulators (velars, bilabials, nasals) lead to longer durations than tip-of-tongue sounds (dentals, alveolars).

• Short vs. Overlong ratio: $1:2:3$

9. Coarticulation

• Definition: Overlapping production of two or more phonetic segments. Influence of phonetic context on a segment.

• Types:

  • Right to Left (RL) / Anticipatory (Backward): Speaker anticipates upcoming sounds (e.g., lip protrusion in "spoon" prepared before the vowel).

  • Left to Right (LR) / Carryover: Characteristics of a sound influence the succeeding sound (e.g., nasalization of a vowel after a nasal consonant).

• Advantages: Enhances speed/efficiency, prevents unwanted sound intrusion, and overcomes mechano-inertial difficulties.

10. Suprasegmentals (Prosody)

• Definition: Phonological features extending across multiple segments (syllables, words, phrases), often called the "musical" aspects of speech.

• Major Types:

  • Intrinsic Prosody: Signals grammar (Statement = falling intonation; Question = rising intonation).

  • Intellectual Prosody: Stress placement changes meaning (e.g., "REcord" vs. "reCORD").

  • Emotional Prosody: Variations in pitch/loudness to express sadness, anger, etc.

  • Inarticulate Prosody: Non-verbal vocalizations (grunts, sighs, "hmm").

11. Stress

• Definition (Two Viewpoints):

  • Listener: Perceived loudness.

  • Speaker: Greater muscular effort and expiratory force.

• Linguistic Classification:

  • Phonemic/Word Level: Free stress (shifting stress changes meaning, e.g., word "Permit") vs. Bound stress (fixed position, e.g., Czech = first syllable; French = last syllable).

  • Morphological: Fixed relative to a morpheme.

  • Sentence Level: Primary, Contrastive, and Emphatic stress.

  • Trager & Smith (1951) Levels:

  1. Primary ($/'/$)

  2. Secondary ($/ ext{ extsubprime}/$)

  3. Tertiary

  4. Unstressed/Unaccented

• Acoustic Cues: Increment in $F_0$, duration, and intensity.

• Physiology: Stetson (1928) noted increased laryngeal muscle activity and subglottal air pressure ($ext{SubGP}$) relate to stress.

12. Rhythm

• Definition: Pattern of time intervals between occurrences of stressed syllables.

• Rhythm Class Hypothesis:

  • Stress-timed: Stressed syllables occur at approximately equal intervals (e.g., English, Dutch, German).

  • Syllable-timed: Syllables occur at regular intervals (e.g., French, Spanish, Italian, Kannada).

  • Mora-timed: Rhythmic units are moras (e.g., Japanese).

• PVI (Pairwise Variability Index): Calculation of successive vocalic and intervocalic interval patterns (Grabe and Low, 2002).

• Models of Rhythm:

  • Comb Model: Pre-programmed time schedule (open-loop).

  • Chain Model: Each gesture depends on feedback from the preceding one.

  • Isochrony Model: Stressed syllables in stress-timed languages follow equal time intervals.

13. Development of Fluency

• General Trends: With age, pause time reduces, rate increases, and coarticulatory skills improve.

• Starkweather (1986) KG to 12th Grade Data:

  • Global frequency of vocal hesitations decreases by 2 ext{%}.

  • Filled pauses decreased 65 ext{%}.

  • False starts decreased 62 ext{%}.

  • Repetitions decreased 78 ext{%}.

  • Parenthetical remarks increased 85 ext{%}.

• Motor Maturity: Adult-level speech motor control is typically achieved by $8-12$ years.

• Indian Studies (Savithri et al.):

  • 3-4 years: Mostly unfilled pauses, interjections, and revisions.

  • 6-7 years: Disfluencies common on verbs, nouns, and conjunctions; boys show higher percentages.

14. Typology of Disfluencies: Clinical Categorization

• Core Behaviors (Stuttering): Sound repetitions, part-word repetitions, prolongations, blocks. (Involuntary motor breakdown).

• Accessory/Secondary Behaviors: Eye blinking, head movements, facial tension, avoidance. (Learned coping strategies).

• Within-Word Disfluencies: Sound repetitions, prolongations, blocks. (Pathological indicator).

• Between-Word Disfluencies: Whole-word repetitions (relaxed), phrase repetitions, interjections, revisions. (Typically normal/linguistic planning).

• Differential Diagnosis (Types):

  • NNF (Normal Non-fluency): Effortless, no tension, occurs ages 2-5.

  • Stuttering: Presence of tension and SLDs (Stuttering-Like Disfluencies).

  • Cluttering: Rapid/irregular rate, reduced intelligibility, language organization issues.

  • SAAND: Stuttering Associated with Advanced Neurological Disorders (Neurogenic Stuttering due to CNS damage like stroke or TBI).

15. Environmental and Multifactorial Factors

• Demands-Capacities Model (Starkweather, 1987): Stuttering occurs when environmental or internal demands (motoric, cognitive, linguistic, social) exceed the child’s physiological capacity.

• Environmental Triggers: Fast-paced conversation, frequent interruptions, high communicative pressure.

• Affective Factors: Anxiety, fear, and frustration can create a vicious cycle with disfluency.

• Genetic Factors: Familial patterns may compromise neural organization or motor control mechanisms.