I got my timneh in august last year.. she was 4 years old then and she and her former owner didnt get along in the end,, when i got her she could only say a few words.. and she was really pissed,,
after i got her she has never used any of the words she could say before .. but she has learned so much the almost year i have had her.. now she loves learning new words and sounds..
and she sometimes sit and mumble long sentences and i think she is rehersing new words that she hear.. so give your bird a little time and if it wants to talk and feel safe im sure she can learn a lot .,,the mumbling can easily be words she have heard from you and still rehersing before she feel confident to say them out loud..
good luck . she sound like a lovely bird.,,