What is AAC?
Augmentative and Alternative Communication (AAC) refers to all the ways — beyond speech — that people send and receive messages. The term was developed by speech-language pathologists and researchers to describe a broad set of strategies, tools, and technologies that support human communication.
Augmentative means adding to or supplementing existing speech. Alternative means replacing speech for people who do not use verbal language at all. Many AAC users fall somewhere in between, combining a small amount of speech with other methods.
AAC is not a last resort. Research consistently shows that introducing AAC early does not prevent speech development — and in many cases supports it. The goal of AAC is always fuller, more independent communication, whatever form that takes.
Types of AAC
Unaided AAC
Requires no external device or tool — only the person's own body.
- Sign languages (e.g. ASL, BSL, Auslan)
- Key word signing (e.g. Makaton, Signalong)
- Gestures and body language
- Facial expressions
- Vocalisation and approximations
Aided AAC — Low Tech
Uses physical materials with no power source required.
- Communication boards and books
- PECS (Picture Exchange Communication System)
- Alphabet and word boards
- Objects of reference
- Choice cards
Aided AAC — Mid Tech
Simple electronic devices with recorded or synthesised speech.
- Single-message voice output devices (BigMack)
- Step-by-step communicators
- Simple choice devices (Go Talk)
- Static-display SGDs (Speech-Generating Devices)
Aided AAC — High Tech
Dynamic, programmable devices and software applications.
- Dynamic-display SGDs (Tobii Dynavox, PRC-Saltillo)
- AAC apps (Proloquo2Go, TouchChat, Snap Core First)
- Text-to-speech software
- Eye-gaze systems
- Switch-access and head-mouse systems
Who Uses AAC?
AAC is used by people of all ages, across a wide range of conditions and circumstances. Anyone whose natural speech is absent, limited, or temporarily unavailable may benefit. Common groups include — but are not limited to:
Autism Spectrum Disorder
Including nonspeaking and minimally verbal individuals
Cerebral Palsy
Where motor impairment affects speech production
Developmental Language Disorder
Supporting language learning and expression
Aphasia
Language loss following stroke or brain injury
Degenerative Conditions
ALS / MND, Parkinson's, Huntington's disease
Temporary Conditions
Post-surgery, intubation, severe illness
Key Principles
Presumption of Competence
Every person is assumed to have the potential to communicate and learn. AAC practitioners start from this position regardless of diagnosis or age.
Total Communication
Using all available means — speech, signs, symbols, devices, and gesture — to support understanding and expression. No single method is preferred over another.
Aided Language Stimulation (ALgS)
Communication partners model AAC by using the device or board alongside spoken words, giving the AAC user examples to learn from — just as children learn to talk by hearing others speak.
Robust Vocabulary
Effective AAC systems provide access to core vocabulary (high-frequency words usable in many contexts) as well as fringe vocabulary (topic-specific words). Core words such as "more," "go," "want," and "stop" make up the majority of everyday language.
No Prerequisite Skills
There is no cognitive, physical, or developmental baseline a person must reach before AAC is appropriate. This outdated "candidacy" model has been replaced by the principle that AAC is available to everyone.
Videos
Embedded from YouTube using the privacy-enhanced player. Videos are from hospitals, school districts, and speech-language therapy organisations.
What is AAC? Augmentative and Alternative Communication
Cincinnati Children's Hospital Medical Center
Augmentative and Alternative Communication (AAC) Devices
DIT Labs — Fairfax County Public Schools
Learn How Students Use AAC Devices to Learn and Speak
Community Consolidated School District 89
What is AAC?
The Speech & Language Center
Trusted Public Resources
ASHA — American Speech-Language-Hearing Association
Public information pages on AAC, including what it is, types, and who it helps.
asha.org
ISAAC — International Society for Augmentative and Alternative Communication
Global organisation dedicated to AAC. Introductory resources, position papers, and global community.
isaac-online.org
Communication Matters (UK ISAAC Chapter)
UK-focused AAC information, fact sheets, and resources for families, educators, and professionals.
communicationmatters.org.uk
PrAACtical AAC
A free blog and resource hub maintained by AAC researchers. Evidence-based strategies, downloadable materials, and implementation guides.
praacticalaac.org
Think AAC (Australia)
Free learning modules, implementation support, and evidence-based guidance for Australian educators and families.
thinkaac.com.au
Project Core — University of North Carolina
Free professional development modules and downloadable core vocabulary communication boards for educators and SLPs.
project-core.com
Cboard — Free Open-Source AAC Web App
A free, open-source AAC communication board application available in many languages. Runs in any browser.
cboard.io
NHS — Communication and Autism
Plain-language NHS guidance on communication support and AAC for autistic people and their families.
nhs.uk
📝 A Note on This Page
The information on this page draws from publicly available, openly licensed materials produced by ASHA, ISAAC, and peer-reviewed research. It is intended as an introductory guide and does not constitute professional advice. For individual assessments and recommendations, consult a qualified Speech-Language Pathologist (SLP) or Speech and Language Therapist (SLT).