Alexa type thingy but only has music entry. Listens to your humming and plays along. Communicates with sound gestures instead of words.
Will listen to you and your family's voices and can sing along using their and your voice, or some canned pre-existing voices.
It harmonizes, plays the guitar
and sax, or a symphonic orchestra and choir. If it recognizes the song or piece, it looks it up for you and plays it in karaoke mode, fit to your tones, while mimicking the original singer's voice and choir's sound.
As it gets to know you better it improvises and makes slight changes, creating your own unique internal jokes, and playing your favorite music without having to depend on collective industrial trends.