Augmentative and alternative communication (AAC) overview​

These pages were written to provide AAC information for non-clinicians. Guidance and resources designed for SLTs working in this area can be accessed in the Clinical Guidance portion of our website

Last updated:  May 2024


This information was written by a group made up of AAC users, family members of AAC users, and speech and language therapists (SLTs).

These pages are a starting point to AAC for new users, their families, carers, communication partners and the wider public. The aim is to give an introduction to:

  • What AAC is
  • The different types of AAC
  • How AAC can be used
  • How AAC can be physically accessed in different ways
  • The job of the SLT in helping a person to use AAC well

An advice section for SLTs is available. This has more detail than contained in these pages. Everyone is welcome to read the section for SLTs.

A position statement for policy makers is also available. The position statement has an outline of the areas covered by both these pages and the SLT pages.

In these pages we use identity-first language. This means we talk about the AAC first and then the user. We say ‘AAC user’ because a survey found that most people preferred this. We know that some people prefer other words. For example, some people prefer ‘person who uses AAC’, while others prefer ‘multimodal communicator’. SLTs know that they should respect and use the words each person prefers.

In these pages we use words such as ‘people’ or ‘individuals’ when referring to AAC users of all ages. We only use ‘child’, ‘young person’ or ‘adult’ if a statement is just about that age group.

What is AAC?

AAC stands for ‘augmentative and alternative communication’. It is an approach to communication that helps people to communicate or to communicate more clearly and easily.

  • ‘Augmentative’ means that it helps to make communication clearer. This may be by helping people make their speech clearer or it may be by helping them to communicate something that a person is trying to say using things like body language or facial expressions.
  • ‘Alternative’ means a different way to communicate. This may be instead of speech or it may replace some behaviours for some users.

Some people will use AAC in an augmentative way, others in an alternative way. Some will use it in both ways. How AAC is used will depend on the user, their needs and their diagnosis/diagnoses.

There is a glossary, or special dictionary of words linked to AAC, at the end of these pages.

Types of AAC

There are lots of different types of AAC. They are often grouped into two categories – ‘unaided’ and ‘aided’.


Unaided AAC

‘Unaided’ AAC uses no extra things to communicate. This type of AAC could include signing, body language and facial expressions.

Signing can be either sign language (e.g. British Sign Language or Irish Sign Language) or keyword signing vocabularies or sign supported speech (such as Makaton or Signalong). In keyword signing the signs are used to support or replace words that come up in the same order as they would in spoken language.

Types of unaided AAC

It is likely that an AAC user will use more than one of the following types of unaided AAC and will also use some types of aided AAC:

• vocalisations* (e.g. laughing, crying, making sounds)
• facial expressions*
• body movement and/or gestures* (such as turning the head away, nodding, pushing something/someone away, grasping something / someone, pointing)
• eye movements and fixed gaze* (e.g. looking at something to show an interest in it)
• signed vocabulary and sign supported speech (such as Makaton or Signalong)
• sign language (e.g. British Sign Language or Irish Sign Language)
• re-voicing (where a familiar communication partner says the AAC user’s message for other listeners)
• eye-movement signals (e.g. looking up for yes and looking down for no).


*These types of unaided AAC are often called ‘non-verbal communication’. Non-verbal communication is used by many people, including non-AAC users. However, AAC users might rely on this more often than non-AAC users.

Please see the glossary for more information on the different types of signs, communication partners, eye gaze, and eye pointing.


‘Aided’ AAC

‘Aided’ AAC uses equipment or resources, such as communication boards, books, objects, charts, apps, tablets and computers.

Aided AAC can be split into two groups: ‘powered’ (anything that uses a battery or electricty) and ‘paper’ (anything that is paper based). Both powered and paper systems may use objects, picture symbols, written words or a combination.

The type of AAC used depends on the person using it and their needs. Often, AAC users will use more than one type of AAC, and many will use lots of different types.

Communication Matters (the UK’s AAC charity) has a useful page about AAC and the different types available (Communication Matters, 2024)

Types of aided AAC

Both of the following systems work well for different people. Many AAC users use both powered and paper-based AAC. It is likely that an AAC user will use more than one type of aided AAC and they will also use some types of unaided AAC.

Paper-based Powered
Has words and ideas represented by letters, written words, sound recordings of spoken word, pictures, symbols, photos or real objects.
Is anything not electrical. For example, an alphabet board or a communication book. It could include the use of a Perspex frame that objects, pictures or symbols can be attached to.  Has a source of power e.g. battery or plugged in to charge. 

Is a special device (e.g. a specific communication aid, a tablet, or a personal computer). 

May be designed just for AAC or may be tablets or computers running AAC programs or apps. 


Software packages can be used to make a resource or it can be made by hand.  Sometimes software can help decide how the vocabulary is organised.    Software packages can organise vocabulary. Other software can be used (such as cameras, stories, apps and tools for voice or message banking). 
Software will run on an operating platform.  
Size and weight can be changed to suit the user’s needs.  Different weights and sizes are available. 
Can be attached to equipment with easytofind solutions (e.g. hook-loop touch fastenings).  Will need a specific mounting system to attach to a wheelchair or table. 
Communication partner shares responsibility for the speech/voice output.   The device creates speech/voice output. This includes access to pre-stored voices and message banking. 
May have a messagebuilding strip if the pictures/symbols can be moved around.   May have an on-screen summary of the message being built. 

Please see the glossary for more information on symbols, voice and message banking, mounting systems, communication partners and voice output (VOCA).

Choosing the right AAC

An SLT will work with the AAC user to find the system that works best for them. The SLT will think about how the AAC will be used; for example, who the person communicates with and what activities they do.

To find the right AAC, it is important to think about lots of things. For example:

  • Does the AAC system need to support their language development and/or their communication success, or substitute for speech?
  • Does the AAC user need something to use outdoors?
  • Does the AAC user need something lightweight?
  • Does the AAC user need something they can use during video calls?

Decisions depend on the AAC user, their needs and their life. An SLT will think about all of this when planning and starting to help an AAC user to use their AAC. There is no ‘best system’ out there. AAC is personal and the best system is one that fits the needs of each AAC user across time.

Using AAC in real life

AAC is for use in real life. AAC should not be used just in speech and language therapy sessions. Learning to use AAC is a team effort, involving the AAC user, partners, parents/carers, siblings, SLT, educators, personal assistants, other therapists and the wider community.

Some AAC users will use AAC from childhood through to adulthood, others will need it in later life due to illness or life-changing events. For some AAC users, AAC will be needed or used all the time. For others, it can be used on a part-time basis just when they need it. Some AAC users may find they need to use AAC more if speaking gets harder or less if speaking gets easier.

When helping find the AAC system that is right for each individual the SLT will think carefully with the person and their supporters and find a system that will work best for them. This may mean using more than one type of AAC. Many AAC users use different AAC resources so that they have what they need to communicate in different places and with different people.

It is important that a way to use the AAC system is found that is right for each AAC user’s physical abilities. There are many different types of equipment and ways to use them. SLTs will work with occupational therapists and other healthcare professionals to find the right way to use an AAC system.


The four Ps of AAC

There are lots of different kinds of AAC, but they all use the same basic components or ingredients to make them work. According to SLT Helen Robinson (2022), all AAC is based on a combination of the following four Ps: paper, powered, person and partner. The actual combination will differ from person to person.

  • Person – this is the AAC user. It is important to think about all the ways that a person can communicate. Communication can be with sounds, pointing, eye contact or eye pointing (looking), sign, body language and words. All forms of communication should be valued and ‘listened’ to. See also ‘What is AAC?’ and the information on ‘unaided’ communication.
  • Partner – the communication partner is really important in helping a person communicate. Attention, patience, helping when a misunderstanding happens and being willing to keep trying are all important in helping to build meaningful communication.
  • Paper – this is any kind of AAC that does not need power. It may include alphabet boards, symbol charts, choice boards, communication books, photos and writing.
  • Powered – this is any kind of AAC that uses a battery or electricity. These types often ‘speak’ out loud to listeners. They may include communication aids just for AAC, or apps or other programs available on regular communication devices, such as mobile phones and tablets.

All the 4 Ps are equal and all have value and use. Some people make the mistake of thinking that powered is always better than paper. There are many reasons why paper can be better than powered solutions. For example, paper is often lighter and can be used in more places (e.g. a laminated board can be used in a swimming pool). Some people prefer paper solutions because they find them quicker and easier to use. A good AAC system for an individual will often include both powered and paper AAC.

The words used in AAC

The words in/on the AAC system can be shown in different ways. Some AAC will have codes as well as words, for example LOL (‘laugh out loud’) or BRB (‘be right back’).

Words can be written down as text to be read by the AAC user and/or communication partner or spoken aloud by a computer .

Some AAC systems have the words displayed by symbols or photographs. Others use physical objects, e.g. tapping or bringing attention to an actual cup to mean “thirsty”.

In some types of AAC, the words will be on display all the time. These are called ‘static displays’, such as on a paper chart or a laptop keyboard. Other displays change so you can see/hear different words as you select different things. These are called a ‘dynamic displays’, for example on a tablet device or laptop screen. Another option is a ‘visual scene display’. This shows a picture to create a base for understanding a situation. For example in a picture of a playground, the words are accessed by hitting a spot on the picture, e.g. swing, girl on swing.

How words are put in/on the AAC system will depend on the AAC user’s needs and abilities. The SLT will help the AAC user to think carefully about where to put the words. There are different ways of grouping words together. For example, they could be put into categories (such as nouns/naming words together; or according to topics, such as transport or music ) or they could be grouped in a different way. The aim is to help the AAC user find the words they need as quickly and easily as possible.

See ‘learning resources’ section of RCSLT resources for SLTs for some video examples.

Who uses AAC?

People need AAC for different reasons. Some individuals use AAC for their whole life, others use AAC because of changes that have happened in their lives. There are many different reasons for using AAC, so AAC users are very different from each other. Research says that around 1 in 200 people in the UK may need AAC (Webb et al, 2023). Experts think that the actual number could be higher, but at the moment this is the number used to plan specialist AAC services and the linked SLT services in the UK.

The people most likely to need AAC are those diagnosed with:

  • Cerebral palsy
  • Motor neurone disease
  • Stroke
  • Learning disabilities, including profound and multiple learning disabilities
  • Autism
  • Attention deficit hyperactivity disorder
  • Multiple sclerosis
  • Parkinson’s disease
  • Alzheimer’s disease and other forms of dementia

The range of needs is wide and there will also be a wide variety of needs within each of those diagnoses.

An SLT may suggest that AAC could be useful for people with the following speech and language diagnoses:

  • Aphasia
  • Aphonia/dysphonia
  • Cognitive communication impairment
  • Developmental language disorder
  • Dysarthria/anarthria
  • Dyspraxia
  • Speech sound disorder
  • Selective mutism
  • Social communication difficulties
  • Stammering (dysfluency)

See next section on ‘RCSLT resources’ for more information on these diagnoses.

The communication team

SLTs will often take the lead in introducing AAC to users or potential users. They are specially trained to help those with communication and language difficulties. Each SLT works as part of a team.

The AAC user is at the centre of the decision-making team. It is important that the AAC user has a say about their AAC needs during discussions. They should be happy with the AAC system identified. With it they can build confidence using it in different places and with lots of different people. Any type of AAC is not a ‘magic wand’ that will solve all communication issues overnight. It takes time and support to learn to use AAC, and even more time and support to learn to use it well.

It would be very difficult for the AAC user to learn to use AAC with just the SLT alone. This is where the rest of the team come in:

  • families, carers and friends
  • other professionals such as teachers and teaching assistants
  • occupational therapists
  • physiotherapists
  • nurses
  • technicians
  • clinical and healthcare scientists
  • psychologists
  • support workers and personal assistants
  • product suppliers

Some of these people work with AAC users through the NHS. Others work through independent practice.

How support for AAC is given varies. It is decided at a local level and should take into account individual needs. Support will vary between the four nations of the UK, and sometimes even within each nation. If you have any questions, please ask your SLT for advice and guidance about how things work in your area. Communication Matters, the UK’s AAC charity, may be able to help.

What to expect from speech and language therapy

Speech and language therapists help AAC users in four main ways:

  1. Assessment – the SLT gathers information about a person’s needs and thinks about whether AAC will be useful for them. If the person and the SLT agree that AAC will be useful then the SLT will work with that person and their team to make a management plan. This includes deciding which AAC is right for the individual to try.
  2. Provision (providing the AAC) – if using aided AAC the SLT will think about how the words and language will be shown in the AAC. This could be as written words, symbols, pictures or a mix of these. They will also think about how language is organised to make it as easy as possible for the AAC user. The AAC system needs to be useful in the activities and places that are important to the AAC user. If using unaided AAC, the same sorts of decisions will be made about what vocabulary to learn and use with the unaided system, e.g. the sign or gesture for ‘again’.
  3. Use/Implementation – AAC is of no use if the AAC user does not know how to use it or if they do not have it everywhere they need it. SLTs will help the AAC user get the best use of the system at home and in all other relevant areas, such as school, work and general life. The SLT will give support, advice and training to the AAC user and to their main communication partners. The SLT should keep working with the AAC user for as long as is needed to make sure they are going to be able to communicate as best they can (this will vary according to each individual AAC user’s needs.)
  4. Management – SLTs will often assess an AAC user’s needs again to be sure that the AAC they have is still right for them. Often it will be, but there will be times when changes are needed, for example as skills improve or medical conditions change what the AAC user needs. SLTs will also plan ahead for changes that will happen in an AAC user’s life, such as if the user moves schools, changes to adult services, or has a medical condition that will develop in a predictable way.

Guidelines for SLTs working with AAC users

The advice document for SLTs contains 16 guidelines. The RCSLT has written these guidelines to tell SLTs how they should work with AAC users.

Here is a summary of these guidelines (remember– there is a glossary for the specialist words included in these pages):

  1. SLTs will respect AAC users, their identities and their views. They will make sure AAC users get AAC services in a personal and timely way.
  2. AAC systems can take time to learn to use. AAC users will be given time and support to learn to use their system and any up-dates or changes made to it.
  3. SLTs will respect the AAC user’s cultural, social and language needs when making choices about an AAC system. This includes providing AAC that has:
    • The right language(s)
    • The right content
    • Appropriate symbols, e.g. skin tone, gender neutral job roles
    • Appropriate voices, e.g. gender, accent
  4. SLTs will be aware of the Communication Access UK training and make use of it. This is free training that anyone can do.
  5. SLTs and other professionals will use tools ,such as IPAACKS, to check what skills they have and what they need to learn more about. IPAACKS stands for ‘Informing and Profiling AAC Knowledge and Skills’. It is a free tool from NHS Education Scotland. Please see the following pages for more details:
  6. AAC services are set up differently across the UK. SLTs will know about the AAC services in their area and use them when needed. They will always consider the AAC user’s views about AAC services.
  7. SLTs will work in teams that include other professionals, the AAC user and their family/carers, etc. to ensure a good service is provided, and to build an AAC system that can be used in all areas of a user’s life.
  8. SLTs will assess the AAC user’s speech, language and communication abilities. They will use this information to get ideas about what AAC and support is needed so that everyone can help the AAC user in the best way possible and allow the AAC user to become as independent as possible in their communication.
  9. SLTs will know about AAC assessment tools and use them appropriately. They will keep their knowledge up to date.
  10. SLTs will share their ideas, plans and advice with the AAC user and everyone in the communication team. SLTs will write down what is going to be done next and will check back later to see if plans have worked. They will then think about next steps for the AAC user and make note of approaches that may be useful for them in the future.
  11. SLTs will know about the different approaches and strategies that help AAC users. They will use approaches that work for the AAC user, whatever their diagnosis/diagnoses may be.
  12. SLTs will use their general speech and language therapy knowledge and strategies when working with AAC users. AAC users will have full access to speech and language therapy, which will not be stopped or held back due to their AAC use.
  13. SLTs will know about communication partner strategies and training. They will help people who communicate with AAC users, either by providing or signposting to such training.
  14. Good communication partners are very important to AAC users. SLTs will make training for these partners part of any therapy plan.
  15. SLTs will plan ahead for changes that the AAC user may face. These include life changes (e.g. moving to a new school/work/hospital/home) or technology changes that may alter the AAC system.
  16. SLTs will keep good records about their decisions. If an AAC user needs to have a new SLT the new SLT should read about what has already happened and help the AAC user to keep moving forwards and making progress.



  • Augmentative and alternative communication (AAC) – AAC either helps to make speech clearer to the listener or gives a person a way to communicate instead of speech.
    • Augmentative means as well as speech, adding to speech, improving or making it clearer.
    • Alternative means instead of speech.
  • Access method – how a person uses their AAC; for example, pointing with a finger, selecting with their eyes or another body part, using a joystick or switch and many other methods.
  • Aided communication – physical communication tools. These may include a communications board, alphabet boards, and electronic devices running programs or apps.
  • Alternative access – ways for a user to use AAC when they cannot point. These may include eye-pointing, partner-assisted scanning (using the communication partner’s finger), Eye-transfer (E-Tran) frames, switches, joy sticks, head mouse, etc. This is also called indirect access.
  • Communication device – the paper or powered AAC system a person uses.
  • Communication partner – the person having a conversation with the AAC user.
  • Conversation partner – A conversation partner is anyone that a person using AAC has a personal or relationship-based conversation.Partners can be both of the above.
  • Conversation training/Conversation partner training – This describes a range of approaches training communication partners of AAC users. The approaches support partners to understand why differing communication or conversational strategies may be needed, and how to use these strategies to help the AAC user to demonstrate their abilities, wants and needs.
  • Communication system – if the AAC uses symbols or text, how it is set up or designed, and how the user accesses it. Some people also say communication system to mean communication device.
  • Direct access – the AAC user points to the page or screen with their finger.
  • Encoded language – when codes stand for words or phrases, e.g. LOL for ‘laugh out loud’.
  • Electronic AAC – this means the same as ‘powered AAC’ (see below for details).
  • Expressive language – the language we use to communicate with or talk to others. Anything we use to get a message across to other people. It is the opposite of receptive language (see below).
  • Eye gaze – using a computer mouse that is controlled by the eyes, rather than the hands and fingers.
  • Eye pointing – pointing/looking with the eyes to give a message. For example looking at words, symbols, objects or people
  • High-tech AAC – AAC that uses a battery. This is an old term, most people in the UK now use the term ‘powered AAC’ or ‘electronic AAC’ instead of this.
  • Indirect access – ways for a user to use AAC when they cannot point. These may include eye-pointing, partner-assisted scanning (using the communication partner’s finger,) Eye-Transfer (E-Trans) frames, switches, joy sticks, head mouse, etc. This is also called alternative access.
  • Language representation system – how words and ideas are displayed in the AAC. May include words, symbols, photos, objects of reference and sign language.
  • Low-tech AAC – any AAC that does not have a battery. This is an old term, most people in the UK now use the term ‘paper-based’ or ‘paper AAC’ instead of this.
  • Message banking – when a person uses either their own or someone else’s voice to make recordings of sentences for an AAC device. This is often done by people who know they will need to use AAC in the future.
  • Mounting system – how AAC is fixed to wheelchairs, beds, tables etc
  • Neurodivergent – sometimes abbreviated as ND. Means having a mind that functions in ways which diverge significantly from the dominant societal standards of “normal” (Walker, 2021, pg 25-33).
  • Neurodiversity – is the diversity of human minds;(Walker, 2021, pg 25-33) It applies to us all.
  • Neurotypical – often abbreviated as NT, means having a style of neurocognitive functioning that falls within the dominant societal standards of “normal” (Walker, 2021, pg 25-33).
  • Non-powered – AAC which does not use electricity, usually paper-based.
  • Objects of reference – using an actual item to give a message, e.g. holding up a CD case to ask for music to be put on.
  • Paper/paper-based AAC/solutions – any AAC that does not have a battery. Some people used to use the term “low tech”.
  • Partner assisted scanning – the communication partner points to and/or says the name of things to help the AAC user communicate them. May be visual (where the communication partner points to things), auditory (where the communication partner says things or reads them out) or both visual and auditory together. The kind used will depend on the AAC user and what they can do.
  • Powered AAC/powered solutions – AAC that uses electricity, either mains or battery powered. This can include apps on tablets, special AAC devices and PC programmes. They often produce a voice output that communication partners can listen to.
  • The Royal College of Speech and Language Therapists (RCSLT) – the organisation that helps SLTs in the UK and makes sure they do a good job.
  • Receptive language – language that we understand when people are communicating with us. Anything other people use to get a message across to us. It is the opposite of expressive language (see above).
  • Re-voicing – when someone who knows the AAC user well explains to someone less familiar what they are saying.
  • Robust system – AAC that can be used in as many settings as possible. This may need more than one type of AAC, which the user will use at different times (eg. using a laminated communication board in a swimming pool, but a voice output tablet at other times.) It is AAC made suitable for different places and times.
  • Scaffolded conversation – also known as supported or co-constructed conversation. Anything that helps build effective communication. It may include visual prompts, starter phrases, word prompts or checking that a communication partner has understood meaning.
  • Semantic/schematic – a way to organise words. Lets a user build a sentence on one page of their AAC, but means symbols will be repeated on lots of pages. Words such as ‘I’ may come up on nearly every page.
  • Sign – British Sign Language (BSL) (and sometimes Irish Sign Language (ISL) in Northern Ireland) are sign languages, but much AAC signing is a sign vocabulary. This means the signs are used to support or replace words that come up in the same order as they would in spoken language. Sometimes called ‘Sign Supported English’, signed vocabularies are often used to help receptive as well as expressive language. This is different to BSL, which has its own grammar and syntax and is a full language.
  • Switch (access) – A switch is a button that can be pressed to let someone with a physical disability access a wide range of technology, from a light or fan to a voice output communication aid (VOCA) or computer. Switches come in a wide variety of sizes and designs and can be accessed using different body parts.
  • Symbols – language-based pictures used in AAC to represent the words.
  • Taxonomic – a way to organise words. Taxonomic organisation keeps words of the same type together. For example, a page of nouns or a page of clothes words. Users will need to use lots of pages to build a sentence, but can find the main words giving key information quickly.
  • Unaided communication – the AAC user’s body helps to give messages. This may include sign, gesture, facial expression, body language, where a person looks, vocalisations or making sounds, and re-voicing (see above).
  • Voice banking – when a person uses their own voice to create an AAC ‘voice’. This voice may end up sounding more like the user’s voice than other voices available from suppliers.
  • Voice donating – a process through which regional dialects are collected, offering AAC users speech output that more closely resembles their own regional dialect. Currently, this is not automatically available on all devices.
  • Voice Output Communication Aid (VOCA), also called speech generating device (SGD) – Powered devices that create a ‘voice’ for communication partners to listen to. This may be pre-recorded speech (digitised) or artificial speech (synthesised) or both. Most include software packages to support the types of words the person wants to use.


Communication Matters, What is AAC, (Accessed 12 April 2024) Available at:

Alzheimer’s Society, Types of Dementia  (Accessed 20 March 2024)  Available at:

NHS Education for Scotland (2014). IPAACKS Informing and Profiling Augmentative and Alternative Communication (AAC) Knowledge and Skills. (Accessed 12 April 2024) Available online:

Robinson, H. (2022). The four Ps of AAC.

Walker, N. (2021) Neuroqueer heresies : notes on the neurodiversity paradigm, autistic empowerment, and postnormal possibilities. Fort Worth, TX: Autonomous Press.

Webb, E.J., Meads, D., Lynch, Y., Judge, S., Randall, N., Goldbart, J., Meredith, S., Moulam, L., Hess, S. and Murray, J. (2021) ‘Attribute selection for a discrete choice experiment incorporating a best-worst scaling survey’ Value in Health24(4), pp.575-584.



Lead Author

Professor Janice Murray

Supporting Authors

Sinead Barker

Bronagh Blaney

Claire Cardador

Mary Dunningham

Gillian Hazell

Jenny Herd

Catherine Martin

Beth Moulam

Jamie Preece

Katie Radtke

Katherine Small

Emma Sullivan

Helen Whittle

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