When I was a child I was ultra shy. The middle child in my family, I developed the pattern of letting my older sister do the decision-making and my younger brother handle conversation.
That pattern made me comfortable yet did little to help me break away from the communication barriers I created. What this means is, I had problems entering conversation, getting to know people, making decisions and feeling confident around people. Later in life when encouraged to speak up at meetings or to groups, I suffered physical anxieties like diarhea triggers, focus issues, cold hands, and weak knees.
Researchers tell us that social phobias like public speaking anxiety start in childhood with shyness. If we don't address them, they progress through adulthood.