Hi and welcome.
Where is it saying that? In an app? When you switch from screen to screen on your phone?
If it is in an app (and it sounds as if it must be) look into the app's settings. I have never had an app do that, but if it is happening, someone decided that it should be a feature. Nit sure what they would call it though.
Next time it happens, hit whatever button you use to get into the phone's settings (or look for little gears on the screen) and the app settings will pop up. Root around in there, and you will find where to shut her up.
if you can't find it, ask another question and put the name of the app where it happens, and maybe we can help you figure it out.
Hope this helps.