The Ring of Human Influence affects dialogues also, although you might be able to get more with a natural 18.
For instance, without the ring, with a natural CHA of 9, the woman in the back of the Copper Coronet did not offer me the chance to sleep with one of her girls. Also without the ring the Drows at the Ust'Natha bar did not offer me the "special treatment". But when I put on the ring, viola.
While most people would dismiss these dialogues as non-"vital" the choice between sex and no sex, is definitely a life or death decision in my book.
[ 10-11-2001: Message edited by: Yuusuke ]
"Gentlemen! You can't fight in here! This is the war room!" -Dr. StrangeLove
"Never in my life could I have afforded to be raised!" -Fezhak
"I don't want to meet someone who shares my interests. I hate my interests." - Steve Buscemi Ghost World