Junko has the capability to both project a visage of herself on her enlarged pink cell phone and she can communicate through Monobear. The circumstances impact which one she shall be controlling at that moment in time--If there is a person wandering the abandoned island, she'll appear as Monobear and simply portray herself in that role.
If she is talking with someone as her usual self, she won't hold back; AI Junko was programmed to act just like the real Junko (she was even given the girls memories) and her personality will swap every so often to coordinate.
Furthermore, her words and actions may differ depending on the individual she is talking to. For example, she has a strong distaste towards the Future Foundation: Thus, anyone associated with that group is not someone she will likely get along with so easily. Additionally, if Junko encounters any students that were placed in the Rehabilitation Program (aka the SDR2 cast) and they show signs of hope/mention how they do not want to listen to her commands anymore, she'll try to persuade them otherwise. Even if it's unsuccessful, she can always pull a few tricks up her sleeves.