" Professor Ramachandran believes this synesthetic connection between our hearing and seeing senses was an important first step towards the creation of words in early humans. According to this theory, our ancestors would have begun to talk by using sounds that evoked the object they wanted to describe. For example, words referring to something small often involve making a synesthetic small i sound with the lips and a narrowing of the vocal tracts: Little, teeny, petite, whereas the opposite is true of words denoting something large or enormous. If the theory is right, then language emerged from the vast array of synesthetic connections in the human brain. "
― Daniel Tammet , Born on a Blue Day: Inside the Extraordinary Mind of an Autistic Savant