Free AAC apps.

From easy to complex:

LetMe Talk - Free AAC Talker

With photos

https://my-talker-aac.en.aptoide.com/app

Jellow Basic AAC Communicator

With pictures, signs and sequences

https://play.google.com/store/apps/details?id=com.dsource.idc.jellowintl&hl=en

CBoard

With pictures

https://play.google.com/store/search?q=cboard&c=apps&hl=en

PicTalk AAC

With pictos

https://play.google.com/store/apps/details?id=org.pictalk.www.twa&hl=en

Card Talk

With pictures, for sentence building

https://play.google.com/store/search?q=card%20talk&c=apps&hl=en

Speech Assistant AAC

Written words

https://play.google.com/store/search?q=speech%20assistant&c=apps&hl=en

Weave Chat AAC

Pictos, for sentence building

https://play.google.com/store/search?q=weave%20chat&c=apps&hl=en

TypingTalk AAC Text-to-speech

For text-to-speech

https://play.google.com/store/apps/details?id=com.miyanour.speechassist&hl=en

Spoken Tap-to-talk AAC

Symbols, write-to-text-voice

https://play.google.com/store/search?q=spoken&c=apps&hl=en