The following scene will be a musical. This simply means that at various times through out the scene the players will break into song.
Singing on stage is the terror of many improvisers. There is a feeling that they may be tolerated speaking on stage, but singing would surely lead to their lynching. Not so. The audience really gets behind someone that sings on stage. It is the same for make-a-song, do-run-run, or madrigals. Singing is respected, and if it can be done remotely well it will be loved. A musical requires some musical instrument to work best. Singing from taped music is harder to orchestrate and ruins the magic a bit. Consider the musician as another player with offers and complimentary support in the scene. The musician may offer musical styles to select the mood, and even direct the scene. Musicals are most easily done when there are songs intermixed amongst a regular scene. This allows for advances to be made without having to sing them.
Opera. All words are sung.