Glossary
Searchable terminology from accessibility, web standards, and related fields.
68 results found in AAC.
- Expressive Communication (Expressive AAC, Rich Communication)
- Communication that conveys not just informational content but also emotion, personality, attitude, humor, and social nuance. For AAC users, achieving expressive communication is a significant challeng…
- Eye Gaze Communication (Gaze-Based Communication, Eye Tracking Communication)
- The use of eye movements and gaze direction as a means of communication, either naturally (making eye contact, looking at objects to indicate interest) or through technology (eye-tracking systems that…
- Huffman Coding (Huffman Algorithm, Huffman Tree)
- A data compression algorithm that assigns shorter codes to more frequently occurring symbols and longer codes to less frequent ones, producing an optimal prefix-free encoding. In accessibility and AAC…
- Idiosyncratic Gesture (Personalised Gesture, Idiosyncratic Movement)
- A body-based communicative movement whose form and meaning are specific to one individual (and often to one communication partner), rather than drawn from a shared vocabulary like American Sign Langua…
- Indirect Text Entry (Indirect Selection, Indirect Text Composition)
- A text input method where the number of available input controls (such as switches or keys) is significantly smaller than the number of characters that can be entered. The user selects characters thro…
- Input Rate (Keystroke Rate)
- The speed at which a user can produce individual keystrokes or character inputs, typically measured in seconds per keystroke. Input rate varies dramatically across access methods: touch typists may ac…
- Interaction Symmetry (Balanced Interaction)
- The degree to which conversation partners have equal opportunities and means to participate in an interaction. In face-to-face spoken conversation, interaction is relatively symmetric—both partners ca…
- Keystroke Saving (KS, Keystroke Reduction)
- A metric used to evaluate word prediction and word completion systems, measuring the percentage of keystrokes that a user can avoid by accepting system predictions instead of typing each character ind…
- Keystroke Savings (KS, Key Savings)
- A metric used to evaluate word prediction systems, measuring the percentage of keystrokes eliminated by accepting predictions compared to typing the full text character by character. While keystroke s…
- Lingraphica
- A commercially available computerized visual communication system designed to help people with aphasia communicate through icon-based sentence construction. Lingraphica provides a vocabulary of purpos…
- Lombard Effect (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 Étienn…
- Memory Aid (Memory Wallet, Memory Book, External Memory Aid)
- A tool or device that supports memory function by providing external cues, reminders, or stored information that a person can reference. For people with dementia or other cognitive impairments, memory…
- Multi-Modal Communication (Multimodal Communication)
- Communication that simultaneously uses multiple channels or modes—such as speech, gesture, facial expression, gaze, device output, and body movement—to convey meaning. AAC users are inherently multi-m…
- Partner Training (Communication Partner Training, Interlocutor Training)
- Education and coaching provided to the communication partners of AAC users to help them interact more effectively and supportively. Partner training covers strategies like allowing adequate time for r…
- Perplexity (Language Model Perplexity)
- A standard metric for evaluating language models that measures how well the model predicts a sample of text. Mathematically, perplexity is the inverse probability of the test set, normalised by the nu…
- Personal Narrative (Storytelling, Conversational Narrative)
- The act of telling others about one's own experiences, events, and feelings — a fundamental aspect of human social interaction. Personal narrative serves multiple functions: building and maintaining r…
- Pictograms (Pictogram, Picture Symbols, PCS)
- Simplified pictorial symbols that represent concepts, objects, activities, emotions, or places, widely used as a form of augmentative and alternative communication (AAC) and as a visual support for au…
- Picture Communication Symbols (PCS, Boardmaker Symbols)
- A widely used graphic symbol system for augmentative and alternative communication (AAC), consisting of simple, colorful line drawings representing words, phrases, and concepts. Developed by Mayer-Joh…
- Picture Exchange Communication System (PECS)
- A structured augmentative and alternative communication (AAC) system that teaches individuals to use pictures to communicate with others. Developed by Andrew Bondy and Lori Frost in 1985, PECS uses a …
- Pre-Programmed Message (Stored Message, Canned Response, Pre-Set Phrase)
- A message or phrase stored in an AAC device that can be quickly retrieved and spoken without requiring real-time composition. Pre-programmed messages trade expressiveness for speed—they enable faster …