Glossary

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AAC Abandonment(also: AAC Device Abandonment, AT Abandonment)

The widespread phenomenon of users discontinuing their use of augmentative and alternative communication (AAC) devices, particularly common among people with aphasia. Abandonment is driven by multiple factors including poor personalization and difficulty customizing devices to…

Acoustic Phonetics

The branch of phonetics concerned with the physical properties of speech sounds, including their production, transmission, and perception as acoustic signals. Acoustic phonetics uses techniques such as spectral analysis, formant tracking, and landmark detection to characterize…

Aided Language Stimulation(also: Aided Language Modeling, Aided Language Input, ALgS)

A communication intervention technique in which a conversation partner models language on an AAC device while speaking, pointing to symbols on the learner's communication system as they talk. This includes describing their own actions, narrating the learner's actions, providing…

Anomia(also: Word-finding difficulty, Anomic aphasia)

Anomia is a language impairment characterized by difficulty retrieving words during speech, particularly the names of objects, people, or actions. It is the most common symptom across all types of aphasia and can also occur as a standalone condition (anomic aphasia). In…

Aphasia Severity Rating(also: ASR Score, Aphasia Severity Rating Scale)

A clinician-administered ordinal scale, part of the Boston Diagnostic Aphasia Examination, indicating the severity of a person's aphasia on a 0-5 range where 0 indicates no usable speech or comprehension and 5 indicates minimal residual difficulties barely apparent to a…

Apraxia(also: Apraxia of Speech, Childhood Apraxia of Speech, CAS)

A motor speech disorder in which the brain has difficulty coordinating the muscle movements needed to produce speech, despite the muscles themselves not being weak. The person knows what they want to say but their brain has difficulty planning and sequencing the precise…

Articulation(also: Speech Articulation, Articulation Skills)

The physical production of speech sounds through coordinated movement of the articulators—tongue, lips, teeth, palate, jaw, and respiratory system. Articulation disorders occur when a person has difficulty producing specific speech sounds correctly, which may involve…

Articulation Disorder(also: speech sound disorder, phonological disorder)

A speech impairment characterized by difficulty producing speech sounds or phonemes correctly. Articulation disorders are classified into three categories: organic (caused by hearing loss or structural abnormalities), motor (caused by neurological conditions affecting motor…

Auditory Comprehension(also: Listening Comprehension)

The cognitive and linguistic ability to understand spoken language in real time, including recognising words, parsing grammar, holding clauses in working memory, and integrating meaning across sentences. Frequently impaired in people living with aphasia, age-related hearing…

Babbling(also: Canonical Babbling, Prelinguistic Vocalization)

The repetitive, syllable-like vocalizations produced by infants typically between 6 and 12 months of age as a precursor to spoken language. Babbling progresses through developmental stages from simple vowel-like sounds (cooing) to reduplicated sequences like "bababa" and…

Canonical Syllable(also: Canonical Babbling, Well-Formed Syllable)

A canonical syllable is a well-formed syllable in infant babbling that consists of a consonant-like closure (closant) produced by an oral cavity constriction followed by a vowel-like opening (vocant). Canonical syllables typically appear between 5 and 10 months of age in the…

Cognitive-Communication Needs(also: CCN, Cognitive-Communication Disorders)

Difficulties in communication that arise from underlying cognitive deficits in areas such as attention, memory, organization, problem-solving, and executive function, rather than from primary language impairments. Cognitive-communication needs commonly result from traumatic…

Communication Diary(also: Communication Notebook, Communication Book)

A low-tech, typically paper-based personal resource used by individuals with communication difficulties to support daily interactions. Communication diaries may contain written keywords, names, drawings, photographs, collaged objects, and other materials that serve as memory…

Communication Impairment(also: CI, Communication Disorder, Communication Disability)

Damage to brain functions responsible for language and memory that impairs the expression and understanding of spoken and written language. Communication impairments can result from neurological disease, stroke, or acquired brain injury, and include conditions such as aphasia…

Conversation Analysis(also: CA)

A qualitative research methodology that studies the sequential organization and interactional dynamics of naturally occurring talk and social interaction. Conversation analysis examines fine-grained details such as turn-taking, pauses, overlapping speech, gaze direction,…

Core Vocabulary(also: Core Words)

A small set of high-frequency words — typically pronouns, verbs, adjectives, and prepositions — that make up approximately 80% of what people say in everyday communication. Examples include words like "I," "want," "go," "more," "help," and "that." In AAC practice, core…

Cued Naming Therapy(also: Cued Naming, Cueing Hierarchy Therapy)

A structured aphasia therapy approach in which clinicians provide progressively stronger hints (cues) to help a person retrieve a target word. Cues may be phonological (providing the first sound or syllable), semantic (giving a related word or category), orthographic (showing…

DIY AAC(also: Do-It-Yourself AAC, Self-Made AAC, Bespoke AAC)

Augmentative and alternative communication tools created or significantly customized by the users themselves rather than prescribed by clinicians or purchased as commercial products. DIY AAC ranges from low-tech solutions like handmade communication diaries and picture boards to…

Developmental Apraxia of Speech(also: Childhood Apraxia of Speech, CAS, DAS)

A motor speech disorder in which children have difficulty planning and coordinating the movements needed for speech, despite having no muscle weakness. Children with developmental apraxia of speech know what they want to say but their brains have difficulty coordinating the…

Disordered Speech(also: Pathological Speech, Atypical Speech)

Speech that differs from typical patterns due to motor, neurological, structural, or developmental conditions. Disordered speech encompasses conditions like dysarthria, apraxia, stuttering, and speech differences from cerebral palsy or Parkinson's disease. For accessibility,…

Dysfluency(also: Disfluency, Speech Dysfluency)

An interruption in the normal flow of speech, including repetitions of sounds, syllables, or words ("b-b-because"), prolongations of sounds ("ssssnake"), blocks (silent pauses where speech is temporarily stopped), and interjections ("um", "uh"). While occasional dysfluencies are…

Dysphonia(also: voice disorder, phonation disorder)

A voice disorder characterized by abnormal pitch, loudness, quality, or resonance of the voice resulting from impaired function of the larynx or vocal cords. Dysphonia can range from mild hoarseness to complete voice loss (aphonia) and may be caused by vocal cord nodules,…

Electrolarynx(also: Artificial Larynx, Electronic Larynx)

A handheld, battery-powered device that produces voice for people who have lost their larynx. The device is held against the neck or cheek and generates vibrations that travel through the throat tissues into the oral cavity, where the user shapes the vibration into speech using…

Formant(also: Vocal Formant, Formant Frequency)

A concentration of acoustic energy around a particular frequency in the speech signal, produced by the resonance of the vocal tract. Formants are labeled sequentially (F1, F2, F3, etc.) from lowest to highest frequency and are key to distinguishing different vowel sounds and…

Fringe Vocabulary(also: Fringe Words, Context-Specific Vocabulary)

Topic-specific or situation-specific words in an AAC system, typically nouns and other content words that are needed in particular contexts but not used frequently across all conversations. Examples include words like "dinosaur" at a museum, "swing" at a playground, or…

Fundamental Frequency(also: F0, Pitch Frequency, Voice Pitch)

The lowest frequency of a periodic sound wave, corresponding to the rate at which the vocal folds vibrate during voiced speech. Fundamental frequency (F0) is perceived by listeners as pitch and is a primary component of prosody — the rhythm, stress, and intonation of speech. F0…

Iceberg Theory of Stuttering(also: Sheehan's iceberg)

A model proposed by Joseph Sheehan (1970) describing stuttering as an iceberg whose visible behaviours - blocks, repetitions, prolongations - are only a small fraction above the waterline. The much larger hidden portion comprises cognitive and affective reactions: avoidance,…

Landmark Theory(also: Stevens Landmark Theory)

A theoretical framework in speech science developed by Kenneth N. Stevens proposing that listeners extract phonetic information from acoustically abrupt events called landmarks in the speech signal. Landmarks mark points of rapid spectral change — such as the release of a stop…

Laryngectomy(also: Total Laryngectomy)

The surgical removal of the larynx (voice box), typically performed as treatment for advanced laryngeal or throat cancer. A total laryngectomy results in the permanent loss of the natural voice, as the vocal folds that produce speech are removed. The airway is also permanently…

Lee Silverman Voice Treatment(also: LSVT, LSVT LOUD)

An evidence-based speech therapy programme originally developed for individuals with Parkinson's disease that focuses on increasing vocal loudness as the primary mechanism for improving overall speech clarity. LSVT trains patients to "think loud" and speak with greater effort,…

Lexical Access(also: Lexical Retrieval, Word Access)

The cognitive process of retrieving words from the mental lexicon during language production or comprehension. Lexical access involves activating the phonological, semantic, and syntactic properties of a word stored in memory. Disorders of lexical access, such as those seen in…

Lombard Effect(also: Lombard Reflex, Lombard Response)

The involuntary tendency of speakers to increase the intensity, duration, and fundamental frequency of their speech when communicating in noisy environments. Named after French otolaryngologist Étienne Lombard who first described the phenomenon in 1911, the effect involves…

Motor Learning(also: Motor Skill Acquisition)

The process by which practice and experience lead to relatively permanent changes in the capability to perform motor skills. In speech therapy, motor learning principles guide treatment design: random presentation order of stimuli, variable practice contexts for each target…

Multimodal Communication(also: Multi-Modal Communication)

The use of multiple channels and resources simultaneously during interaction, including speech, gesture, gaze, facial expression, body movement, writing, drawing, and physical artifacts. All human communication is inherently multimodal, but this concept is especially significant…

Naming Practice(also: Confrontation Naming, Naming Therapy, Picture Naming)

A speech-language therapy technique in which individuals with aphasia are shown pictures of familiar objects and asked to produce the corresponding word. Naming practice is one of the most common and well-evidenced interventions for word finding difficulties (anomia) in people…

Narrative Skills(also: Narrative Competence, Storytelling Skills)

The ability to recount events — real or imagined — as a coherent, temporally ordered, causally linked story that another person can follow. Narrative skills rest on autobiographical memory retrieval, event sequencing, referential clarity (introducing and tracking characters),…

Oral Language(also: Expressive Oral Language, Spoken Language)

Oral language is the system of spoken communication comprising articulation (producing speech sounds), vocabulary (tact or naming), grammar and linguistic structure, and pragmatic or conversational use. It is distinct from written language and from augmentative communication…

Oral Motor Impairment(also: Oral-Motor Dysfunction, Oromotor Impairment)

A condition affecting the muscles and movements of the mouth, jaw, lips, and tongue that are involved in speech production, feeding, and swallowing. Oral motor impairments can result from neurological conditions such as cerebral palsy, stroke, or traumatic brain injury, and may…

Paralinguistic Features(also: Prosodic Cues, Non-Verbal Speech Features)

Aspects of spoken communication that convey meaning beyond the literal words, including pitch, loudness, rhythm, tone, and emotional affect. These features are critical for understanding speaker intent, sarcasm, emphasis, and emotional state but are typically lost in standard…

People Who Stutter(also: PWS, Person Who Stutters, Adults Who Stutter)

An identity-first and community-preferred term for people who experience stuttering, a neurodevelopmental condition involving involuntary speech disfluencies such as blocks, prolongations, and repetitions. PWS affects roughly 1% of the global population. Community usage (PWS,…

Perceptual Analysis(also: Perceptual Judgment, Auditory-Perceptual Analysis)

A method of evaluating speech, voice, or other sounds based on a human listener's subjective auditory impressions rather than instrumental measurement. In clinical speech-language pathology, perceptual analysis is used to categorize vocalizations, rate voice quality, or assess…

Phoneme(also: Speech Sound)

The smallest unit of sound in a language that can distinguish one word from another. For example, the /b/ and /p/ sounds in "bat" and "pat" are different phonemes. American English has approximately 39 phonemes, compared to 26 letters in the alphabet. In accessibility and AAC…

Phonological Development(also: Speech Sound Development, Phonological Acquisition)

The process by which children learn to produce and organise the speech sounds of their language, progressing from early cooing and vowel-like sounds through canonical babbling (consonant-vowel syllables) to recognisable words and complex phonological patterns. Phonological…

Pre-speech Vocalizations(also: Pre-linguistic Vocalizations, Infant Vocalizations)

Sounds produced by infants before the development of recognizable speech, including cooing, babbling, and other vocal productions. Pre-speech vocalizations are important predictors of later articulation and language abilities, and their analysis can help identify children at…

Prelinguistic Development(also: Pre-Speech Development, Prelinguistic Communication)

Prelinguistic development refers to the stages of vocal and communicative development that occur before an infant produces meaningful words, typically spanning from birth to approximately 12-18 months. This development progresses through recognized stages: the Phonation Stage…

Preverbal Communication(also: Prelinguistic Communication)

The stage of communication development before the consistent use of recognizable words, typically occurring in neurotypical children between birth and approximately 12 months of age. Preverbal communication includes vocalizations (babbling, cooing), gestures, eye gaze, facial…

Quality of Communication Life Scale(also: QCL, ASHA QCL)

A self-report assessment developed by ASHA (American Speech-Language-Hearing Association) that measures how communication disorders affect an individual's quality of life. The QCL evaluates domains including socialization, confidence, roles and responsibilities, and independence…

Severe Speech and Physical Impairments(also: SSPI)

A classification describing individuals who have significant limitations in both speech production and physical movement, often co-occurring in conditions such as cerebral palsy. People with SSPI may have little or no functional speech and limited fine motor control, which…

Sign Language Phonology

The study of the smallest meaningful units that make up signs in signed languages, analogous to phonemes in spoken languages. In American Sign Language, signs are composed of phonological parameters including handshape, movement, location (place of articulation), and non-manual…

Single-Case Study(also: Single-Subject Design, Single-Case Experimental Design, N-of-1 Study)

A research methodology in which an individual participant serves as their own control, with systematic measurement of behavior across different conditions such as baseline and intervention phases. The ABA design — where A represents baseline and B represents intervention — is a…