The calm person in the argument usually ends up holding the power. Volume isn’t leverage.

Shouting mostly demonstrates that something has gone wrong for you. The calm person can be heard, can think, and can choose what to say next, while the room reads loudness as a loss of control. That is why the quiet one tends to be believed and asked to decide. Composure is not the same as being right, and it does get you heard.

In the next heated conversation, slow your sentences and keep your hands still. If you cannot manage calm, manage brief and leave. Come back once your pulse has settled, because the point made quietly is the one people repeat.