say command will speak whatever you type
say "hello c4cs"
Useful Options / Examples
-v can change the voice and language
? will show all the voices and language they speak
-f can load a text file
-i can highlight where the computer is in the speech
--interactive=<markup> will change the preference of the highlighter
-o make an audiofile with what is said
say -v 'Tessa' "hello c4cs" say -v ? say -f sample.txt say -i "Hello there, I have become self aware" say --interactive=blue -v 'Alex' "What a nice day" say -o words "Creating a file called words.aiff"