Text Based Augmentative and Alternative Communication (AAC) apps have you type what you want to say. This is not a new type of app. However, more apps are being made with this theme. As a result, it gets a separate section.
Predictable
This is a high-end text-based communication app with good ratings. The app works with switches.
https://itunes.apple.com/us/app/predictable/id404445007?mt=8
https://play.google.com/store/apps/details?id=com.tbox.predictable_4&hl=en_US
Proloquo4Text
This is a very highly rated, high-end, text-based communication app.
https://itunes.apple.com/us/app/proloquo4text-text-based-aac/id751646884?mt=8
Text to Speech!
This is an iPad/iPhone app that says whatever you type. This is simply free and get the job done. The reviews are also pretty good.
https://itunes.apple.com/us/app/text-to-speech/id712104788
Verbally
This app has a good rating. You have to type what you are going to say. The app has a free version that gives you a better idea if you want this app.
https://itunes.apple.com/us/app/verbally-premium/id470081134?mt=8