— Albert Einstein German-born physicist and founder of the theory of relativity 1879 - 1955
Context: The words or the language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The psychical entities which seem to serve as elements in thoughts are certain signs and more or less clear images which can be "voluntarily" reproduced and combined. There is, of course, a certain connection between those elements and relevant logical concepts. It is also clear that the desire to arrive finally at logically connected concepts is the emotional basis of this rather vague play with the above-mentioned elements.... The above-mentioned elements are, in my case, of visual and some muscular type. Conventional words or other signs have to be sought for laboriously only in a secondary stage, when the mentioned associative play is sufficiently established and can be reproduced at will.
Answer to a survey written by the French mathematician Jaques Hadamard, from Hadamard's An Essay on the Psychology of Invention in the Mathematical Field (1945). Reprinted in Ideas and Opinions (1954). His full set of answers to the questions can be read on p. 3 here http://www.pitt.edu/~jdnorton/Goodies/Einstein_think/index.html.