There are more types of AAC. Depending on the user's needs, and budget, you can choose from a variety of options.
NO TECH:
Gestures
Manual Signs
Facial Expressions
Vocalizations
Verbalizations
Body Language
LOW TECH:
Pictures
Objects
Photographs
Writing
Communication boards/books
HIGH TECH:
Speech Generating Devices (SGD)
Single Message Devices and Recordable/Digitized Devices
AAC software that enables dynamic symbol/language representation and that is used with a computer/tablet/smartphone
Unaided AAC does not require special outside tools or any supplemental materials, because it is based on natural communication such as facial expressions, gestures, body language, informal vocalization. It even implies sign languages.
Aided AAC is any device, either electronic or non-electronic, that is used to transmit or receive messages. It can range from communication books or boards to speech-generating devices.
Aided AAC is divided into two categories: low-tech aids and high-tech aids.
The first one refers to non-electronic devices, represented usually by very simple communication books or boards from each the user selects letters, words, phrases, symbols, objects, or images to transmit a message.
The second category includes speech generating devices or voice output communication aid in electronic format. There are usually digitalized, playing recorded words or phrases, or synthesized, using text-to-speech software.