Artic & Phonology
Introduction to Articulation and Phonology
Definition of Articulation: While the general term means "movement," in the context of speech pathology, articulation refers to the process of taking sound from the level of the vocal folds and shaping it into recognized speech sounds or phonemes of a specific language.
Speech Production: This process bridges the gap between individual sounds and actual speech production.
Anatomy of Speech Production: The Articulators
Speech sounds are shaped by specific physical structures known as articulators.
The Pharynx:
Reffered to in lay terms as the "throat."
The pharynx is divided into three distinct medical regions:
Nasopharynx: Located directly behind the nose. This is the area accessed during a COVID-19 swab.
Oropharynx: Located behind the oral cavity (mouth).
Laryngopharynx: Located behind the larynx.
The Velum (Soft Palate):
Composed of musculature and tissue (green part of standard diagrams).
Biological Function: Its primary role is to seal off the nasal cavity during swallowing to prevent food and liquid from entering the nose.
Speech Function: It raises to contact the pharynx, closing the nasal passage for sounds that do not require nasal resonance.
Uvula: This is the visible tip at the end of the velum.
The Hard Palate:
Composed of the palatine bones (blue part of standard diagrams).
It forms the roof of the mouth and houses the teeth.
The Alveolar Ridge:
A specific ridge on the hard palate where the teeth are inserted. It is a critical landmark for the production of many speech sounds.
The Mandible (Lower Jaw):
Articulates at the Temporomandibular Joint (TMJ), where it attaches to the skull.
Biological Function: Mastication (chewing).
Speech Function: Moves up and down to facilitate the production of various speech sounds.
The Teeth:
Biological Function: Mastication.
Speech Function: Act as a point of contact for sounds like $s$ or within the dental ridge.
Malocclusion: A condition where teeth do not close correctly, potentially affecting both chewing efficiency and speech clarity.
The Tongue:
The most important mobile articulator and is divided into three portions:
Tip.
Blade (also called the body).
Dorsum (the back of the tongue).
Biological Function: Manipulates food in the oral cavity and aids in swallowing.
Speech Function: Essential for the production of both consonants and vowels.
The Lips:
Composed of the Orbicularis Oris muscle.
Biological Function: Creating a lip seal for eating and facilitating facial expressions.
Speech Function: Used for labial sounds such as $p$, $b$, and $m$.
Principles of Phonology and Phonetics
Speed of Production: English speakers typically produce $12$ to $15$ phonemes (speech sounds) in a single second.
Graphemes vs. Phonemes:
There are $26$ graphemes (printed letters) in English but $46$ speech sounds or phonemes.
Sound-to-letter correspondence is unreliable. For example:
The letter $c$ represents different sounds in "cat" (the $k$ sound) and "sent" (the $s$ sound).
The phoneme $e$ can be represented in print in multiple ways: $e$ in "peat," $ee$ in "read," $ea$ in "seat," and $ei$ in "receive."
International Phonetic Alphabet (IPA):
A standardized system designed to have exactly one symbol for every phoneme.
IPA symbols are written inside slashes (e.g., $/i/$).
No matter how a word is spelled (e.g., a word spelled with a $c$ that sounds like a $k$), it is transcribed with the standardized IPA symbol for that specific sound.
Phonemes vs. Allophones:
Phoneme: An abstract category of speech sound.
Allophone: Tiny variations of a phoneme that do not change its meaning.
Example: The "Light $l$" in "light" vs. the "Dark $l$" in "pool." In "pool," the tongue contact at the alveolar ridge is weaker, and the tongue may cup in the back.
These sounds look different on a spectrogram (an acoustic measure of energy/frequency) but are accepted as the same sound category by English speakers.
Phonemic: Refers to the idyllic category of allophones.
Phonetic: Refers to the actual, physical sound production being made.
Classification of Vowels and Consonants
The Vowel Quadrilateral:
A diagram representing the oral cavity space. Vowels are created by modifying the shape of this cavity.
High/Front Vowels: Example is "beat," where the tongue is high and forward, making the mouth space small.
Low/Back Vowels: Example is "bought," where the oral cavity is very open and the tongue is not constricted.
Diphthongs: Vowels created by combining two different vowels (e.g., "boy" combines $o$ and $e$; "bite" combines $ah$ and $e$). They are transcribed with two symbols to show the movement.
Consonant Categorization (Manner, Place, and Voice):
Manner: The way the oral cavity is constricted.
Stops (Plosives): Airflow is stopped, pressure builds, and then is released (e.g., $p, b, t, d, k, g$).
Fricatives: Air is forced through a narrow passage, creating a hiss (e.g., $f, v, s, z, h$, $sh$).
Theta ($\theta$): Unvoiced $th$ as in "think."
Thorn ($\eth$): Voiced $th$ as in "this."
Affricates: A combination of a stop and a fricative (e.g., $ch$ in "chicken," $j$ in "jump").
Glides (Semivowels): Movement from a partially constricted to an open vocal tract (e.g., $y$ transcribed as $j$, and $w$).
Liquids (Semivowels): Very little constriction (e.g., $r, l$).
Nasals: The velum is open to allow air through the nose (e.g., $m, n, ng$).
Place: Where the constriction happens.
Bilabial: Both lips ($p, b, m, w$).
Labiodental: Lips and teeth ($f, v$).
Dental (Lingua-dental): Tongue and teeth (voiced/unvoiced $th$).
Alveolar (Lingua-alveolar): Alveolar ridge ($t, d, s, z, n, l$).
Palatal: Tongue contacts the hard palate ($sh, y$).
Velar: Tongue contacts the back of the palate or velum ($k, g, ng$).
Glottal: Produced at the level of the glottis (the opening between vocal folds) (e.g., $h$, or a glottal stop as in "button" pronounced as "bu'on").
Voice: Whether vocal folds vibrate.
Cognates: Pairs of sounds that are identical in manner and place but differ in voicing (e.g., $p/b, t/d, k/g, s/z$).
Speech Sound Development in Children
Timeline of Development:
Birth to $4$ Months: Reflexive vocalizations (crying, fussing, cooing).
$4$ to $6$ Months: Babbling ($ma, ma$, $ba, ba$).
Later Infancy: Variegated babbling (sounds like speech but without intended words).
$12$ Months: Production of first true words.
Intelligibility Thresholds:
$12$ months to $2$ years: $25\%$ to $50\%$ intelligible.
$2$ to $3$ years: $50\%$ to $75\%$ intelligible.
$4$ to $5$ years: Mostly understood.
$5$ years: Should be $100\%$ intelligible (even if some sounds aren't perfectly produced).
Developmental Norms: Charts show the average age (dot) and ranges (bar) for consonant acquisition. These norms help clinicians determine if a child's errors are "developmentally appropriate" or indicative of a disorder.
Speech Sound Disorders (SSD)
Etiology: Potential causes include cognitive delays, gender, socioeconomic status (SES), birth order, motor skills, hearing issues, structural abnormalities, or neurological disorders.
Functional/Idiopathic Disorders: Most speech sound disorders have no identifiable structural cause; the speaker has simply learned to produce sounds incorrectly.
Articulation Disorder: Individual sound errors (motor-based) with no discernible pattern.
Types of Errors:
Omissions/Deletions: Removing a sound.
Substitutions: Replacing one sound with another.
Distortions: Sound is produced incorrectly but recognizable (e.g., Lateralization - "slushy" $s$ out the sides; Dentalization - tongue against teeth for $s$).
Additions: Adding an extra sound (e.g., adding a schwa in cluster reduction).
Word Positions: Errors are categorized as Initial, Medial, or Final.
Phonological Disorder: Pattern-based errors where a child uses underlying linguistic rules incorrectly (e.g., voicing all voiceless initial consonants like saying "van" for "fan").
Phonological Processes: Normal simplification rules children use that they should eventually outgrow.
Clinical Assessment and Treatment
Screening: Brief procedures like conversation samples or reading the Rainbow Passage (contains every phoneme in English). Common tools include the PLS screening and the Fluhardy.
Assessment Components:
Case History: Requires written consent to obtain records from other providers (e.g., schools).
Oral Mechanism/Oral Facial Exam: Physical inspection of structures.
Hearing Screening: Ensures errors aren't due to auditory deficits.
Standardized Tests:
Goldman-Fristoe (GFTA): Common test for consonants.
Fisher-Logemann: Includes both consonants and vowels.
Arizona; CAP (Clinical Assessment of Articulation and Phonology).
Khan-Lewis: A partner form to GFTA for phonological analysis.
Stimulability Testing: Probing if a child can produce a sound correctly when prompted to imitate.
Cultural Diversity: A dialect is a difference, not a disorder. Clinicians must avoid over-identifying or under-identifying disorders in speakers of dialects like African American English (AAE). The DELV (Dialectical Evaluation of Language Variations) is a tool designed to parse these differences.
Treatment Approaches:
Traditional Approach (Van Riper): Sequence of Ear training -> Establishment -> Stabilization (isolation, syllables, words, phrases) -> Transfer/Carryover -> Maintenance.
Minimal Contrast: Using minimal pairs (words that differ by one feature, like "boo" vs "blue") to show how sound changes affect meaning.