The words your loved one reaches for and can't find are the best guide to what to add. So when the patient is signed in on their own (with their own key or number pad, or on a device the family marked as the patient's), two things are kept: a search in the Phrase Library or on the Search page that finds nothing, and a message typed on the Type tab of Communicate that matches no library phrase and none of their own words. The same words are kept once a day. The Letters board and Write never are, and nothing is kept when a family member searches on their own sign-in.
The family (the account owner and the caregiver role) sees them on the words page (Debbie's words), under Things Debbie looked for, with the day and whether it was a search or a typed message. Add to Debbie's words turns one into a word with one tap; Dismiss clears it.
Below the list is a switch to share what Debbie looked for with the speech therapist. It is off unless the family turns it on, and only the owner and the caregiver role can change it. While it is on, speech therapist (SLP) logins on the care team see the list too and can add a word from it. Every other member of the care team never sees it, whatever the switch says, and neither do family and friends accounts.