In high school, his IQ was determined to be 125—high, but “merely respectable” according to biographer James Gleick.[14] Feynman later scoffed at psychometric testing. In the year 1933, in which he turned 15, he taught himself trigonometry, advanced algebra, infinite series, analytic geometry, and differential and integral calculus.[15] Before entering college, he was experimenting with and re-creating mathematical topics, such as the half-derivative, using his own notation. In high school, he was developing the mathematical intuition behind his Taylor series of mathematical operators.
http://en.wikipedia.org/wiki/Feynman
Feynman (in common with the famous physicist Edward Teller) was a late talker; by his third birthday he had yet to utter a single word.
