Partly built: part of this depends on a connection or a switch that may not be on for your account yet. The article says which part.
As the speech muscles weaken, the goal is to keep the person's voice. The cloned voice, tap-to-speak and the sentence builder are the tools; the ALS mode's own phrase library is not built yet, so the app starts with today's core library and says so.
The condition page on the public site tells the full story and ends with the way to create an account.