Open X Terminal from the menu, then type "espeak" and press enter. Then type some text and press enter - espeak will say it (make sure you are in the General profile and have the volume turned up). Close the X Terminal to close the application. You can use other CLI apps in a similar way - some will need command-line arguments.

All CLI apps should have the CLI badge in the application manager list. If one of the apps does not, it's a bug, and should be reported to the application maintainer, so (s)he can fix it