Synesthesia, a peculiar neurological phenomenon whereby the stimulus of one sensory or cognitive pathway automatically and involuntarily cross-activates another sensory or cognitive pathway, is an incredibly interesting and intriguing topic which will be consuming the energies of many a researcher for the foreseeable future, and surely beyond. There are many variations of synesthesia, with grapheme > color, sound > color, and lexical > gustatory synesthesia, among several other varieties, being the most prevalent. The first entails a subject associating a color with a given grapheme (letter or number); the second associates a color with a given sound; and the last produces a taste on the tongue upon hearing a given phoneme or word. Our interest here is limited to the first two varieties of this phenomenon—which by some has been labeled a disorder, and by others a gift.
Persons that experience synesthesia are called synesthetes, and there are different degrees of intensity of the phenomenon from one subject to the next. The history of the study of synesthesia stretches all the way back to Ancient Greece, when philosophers attempted to understand the chroia (what we now refer to as timbre), or color, of music and how to quantify it. Many eager investigations were conducted on the subject in the late-19th and early-20th centuries, until the ascension of behaviorism within psychology rendered the study of such subjective and internal experiences a ticket to academic oblivion. Since the cognitive revolution of the 1980s, however, there has been more and more study of synesthesia, bringing to light some exceptional insights into the functioning of the human mind.
What synesthetes show the rest of us is that language can be richer than we imagine it to be; the associations a word or a sound can actually have stretch well beyond the conventional preconceptions many linguists (writers, translators, etc.) impose on themselves, and consequently the rest of us. Surely, as investigations continue into this fascinating subject—and specifically the ways in which it relates to a person’s linguistic abilities—we shall all acquire a broader appreciation of language in general, and just how dynamic it really is.