"I will not be spoken to like this. When your ready to discuss this calmly let me know."
Or something similar.
Right. You need to set up a boundary on this. In a very calm, matter of fact manner.
First ask if she realizes she is raising her voice at you.
If she continues then ask if she would please lower her voice. (refrain from accusing her of "yelling" or screaming)
If she continues then tell her you will not accept being spoken to in that manner, and if she refuses to discuss things in a normal tone and volume, you will... *insert your chosen consequence here* It could be I'm leaving the room, ending the conversation for now, or what ever you choose.
Then follow up on it... every time, or it means nothing.
Most important is to do this calmly, without being drawn into a fight. It may take a few try's, but it works.
M: A really long time. Crisis: 5 years. She's still worth it.
Life is never made unbearable by circumstances, but only by lack of meaning and purpose. -Viktor Frankl
