To get back to the question...I tend to listen to softer spoken people more easily. I get frustrated with people yelling at me and I find I am listening more to the tone of their voice than to their actual words. I guess that means (for me) that it does imply one's argument will be strengthened by lowering one's voice. I also tend to pay more attention if there is an absence of swearing. I'm not a prude...I just think there are so many amazing words that can get your meaning across without relying on swearing.