When someone calls you, or when you call someone using Nagish, you can choose if you want the other side to hear an intro message at the beginning of the call.
If an intro message is set, the hearing side will hear a short message before we connect your call. The default message asks the other side to be more patient since this is an accessible call.
You can activate, deactivate, or modify the default message under app settings -> Phone Call -> 'Outgoing Call intro Message'.