I am an Australian, and have a love of history. Recently I have been reading up on American History, specifically the period shortly prior to Independance from Britain through to late 1800's. Thomas Jefferson, the third president of the United States, was a very private and quiet man. He gave only two public speeches during his Presidency. Jefferson had a lisp and preferred writing to public speaking partly because of this, indeed he was quoted as saying, "I have no gift for the oratory".
So here we have a man, arguably one of the greatest USA presidents, not to mention of huge intellect who is one of the most frequently quoted men in history, yet he very rarely spoke.
A polymath, Jefferson achieved distinction as, among other things, a horticulturist, political leader, architect, archaeologist, paleontologist, inventor, and founder of the University of Virginia. When President John F. Kennedy welcomed 49 Nobel Prize winners to the White House in 1962 he said, "I think this is the most extraordinary collection of talent and of human knowledge that has ever been gathered together at the White House – with the possible exception of when Thomas Jefferson dined alone."(Taken from Wikipedia).
People who are "quiet" are often thought by others to be "wise" moreso than "shy" or "aloof", as our social phobia trains of thought would have us believe.
I have always been an extremely quiet person. During my time at University I had only three good friends, but my degree involved a substantial amount of "group work" or discussion in tutorials. I had always thought I was unpopular because I never said much in these labs or tutorials. On our last day of University, it was tradition to have your lab coat signed by other students in your year. When I later took off my lab coat I was completely overwhelmed and humbled by what I was reading. The comments were consistently comprised with statements such as "I will really miss your opinions, and input in tutorials", "I have always held you in high regard, and admired you for your valuable input in pracs", "You don't say much mate, but everything you do say always makes complete sense".
It is often the quality of the speech that leaves our moths rather than the quantity that "genuine" people find interesting about us. Till this day I still have only a handful of friends but I am frequently consulted by them for my opinion, on practically all life matters.
I think being someone who has been challenged with the limitations of social phobia symptoms, including being a "quiet" individual, has allowed me to perpetuate my observational skills and I have been told by psychologists and psychotherapists, both in individual and group therapy, that I am an extremely intuative person.
Incidently, I am a Christian, though I respect all opinions when it comes to spirituality. In this sense I do not wish to commence a Bible-bash or force my views on anyone. However, I have provided here are a few scriptures here, and unless you quoted them at a Bible scholar, no-one would have a clue regarding your reference source. You may like to take a look at them (even if you are not interested in Christianity, you will find, I think, they still ring true) Why not quote or adjust to contemporary english, one of the following should you be asked "Why are you so quiet":-
Pro 15:2 The tongue of the wise useth knowledge aright: but the mouth of fools poureth out foolishness.
Pro 12:18 There is that speaketh like the piercings of a sword: but the tongue of the wise is health.
Pro 21:23 Whoso keepeth his mouth and his tongue keepeth his soul from troubles.
Pro 25:15 By long forbearing is a prince persuaded, and a soft tongue breaketh the bone.
Pro 18:21 Death and life are in the power of the tongue: and they that love it shall eat the fruit thereof.
Pro 15:2 The tongue of the wise useth knowledge aright: but the mouth of fools poureth out foolishness.
Psa 52:2 Thy tongue deviseth mischiefs; like a sharp razor, working deceitfully.
Psa 52:4 Thou lovest all devouring words, O thou deceitful tongue