How to prevent Skype on Android from using an external speaker?

Question

Skype

You are talking, then, with a person on Skype, then she turns on the camera so that I can see (not always, apparently, you will understand that I, for my part, am on a mobile phone and not everyone will guess that the video is not always convenient), at this moment my Skype redirects the sound from the personal speaker (which is for the ear, from the side of the screen) to an external speaker and everyone in the neighborhood, well, everything is already becoming audible. The only seen way to transfer back is to hang up and call back, just turning off the video does not help. How to disable this behavior?