Remember that Android and iOS have built-in options to read out text streams. As long as you have the accessibility settings enabled, you can select some text and then select the option to read it aloud. But some apps make the process even easier. Some of these apps are designed for different markets. Consider carefully what market they are first and foremost designed for when reviewing them.
WordTalk from CALL Scotland is fantastic. The only problem is it's now quite challenging to use on recent versions of word.
NaturalReader is a really good, well-designed reading software. An extensive range of voices and a nice clean UI. We recommend looking at this if you need to read out the text from a range of different formats across different operating systems
Speechify is Similar to NaturalReader. Online and as an app. Basic features are available for free.
Wrise. If you are on a Mac DEFINITELY look at wrise. It's beautiful and allows for some markup of speech text
SprintPlus. It does a lot more than just read documents - has a web app that works across browsers, and allows for marking up documents. This a solid tool to look at if you need something to support students with dyslexia
Voice Dream Reader. Read in a wide range of formats. Offline voices from Acapella.
Aloud!. Listen to PDFs. Nice simple UI. Save progress and Free.
And there are some AAC-specific apps that do this but generally, not all three options. Eg
Proloquo4Text. This is a popular choice for people wanting to do speeches with AAC. You can break your speech up into different phrases and categories - and make different elements with different voices if you wish. It's also very good at switching between languages. However it only supports offline voices.