When did Albert Einstein learn to speak, according to the passage you have just

One of the smartest people ever to live, Albert Einstein, changed our society’s development forever with his views, theories, and developments. Einstein was born in Ulm, Germany on March 14, 1879. He spent his youth in Munich. He did not talk until the age of three and by the age of nine, was still not fluent in his native language. His parents were actually concerned that he might be somewhat mentally retarded.
     His parent’s concerns aside, even as a youth Einstein showed a brilliant curiosity about nature and an ability to understand difficult mathematical concepts.  At the age of 12 he taught himself Euclidian Geometry. Einstein hated the dull regimental and unimaginative spirit of school in Munich. His parents wisely thought to transfer him out of that environment.
     Although Einstein’s family was Jewish, he was sent to a Catholic elementary school from 1884 to 1889. However, Einstein’s biographer, Philip Frank, explains that Einstein so thoroughly despised formal schooling that he devised a scheme by which he received a medical excuse from school on the basis of a potential nervous breakdown. He then convinced a mathematics teacher to certify that he was adequately prepared to begin his college studies without a high school diploma. Other biographies, however, state that Einstein was expelled from the gymnasium on the grounds that he was a disruptive influence at the school.