LC Technologies has an eye gaze system for the MacBook. As covered in other threads, there are many AAC apps available for the iOS devices, as well as built in TTS capabilities on Macs, and Mac apps like Keystrokes/Proloquo (the latter is also available for iOS) that can be combined to use switches for speech generation. A head mouse (SmartNav), tongue mouse (Tetramouse) and switches of all types are Mac-compatible. For heavy text reading, apps like Voice Dream can read/display at the same time or separately using the user's visual/audio prefs.
If you can tell us what abilities your PALS has and what device(s) you need to generate speech for, we can be more helpful.
Best,
Laurie