In linguistics, sound symbolism, phonesthesia or phonosemantics is the idea that vocal sounds or phonemes carry meaning in and of themselves.
In the 18th century, Mikhail Lomonosov propagated a theory that words containing certain sounds should bear certain meanings; for instance, the front vowel sounds E, I, YU should be used when depicting tender subjects and those with back vowel sounds O, U, Y when describing things that may cause fear ("like anger, envy, pain, and sorrow").
However, it is Ferdinand de Saussure (1857–1913) who is considered to be the founder of modern 'scientific' linguistics. Central to what de Saussure says about words are two related statements: First, he says that "the sign is arbitrary". He considers the words that we use to indicate things and concepts could be any words — they are essentially just a consensus agreed upon by the speakers of a language and have no discernible pattern or relationship to the thing. Second, he says that, because words are arbitrary, they have meaning only in relation to other words. A dog is a dog because it is not a cat or a mouse or a horse, etc. These ideas have permeated the study of words since the 19th century.
Margaret Magnus is the author of a comprehensive book designed to explain phonosemantics to the lay reader: Gods in the Word. This work describes three types of sound symbolism using a model first proposed by Wilhelm von Humboldt (see below):
This is the least significant type of symbolism. It is simply imitative of sounds or suggests something that makes a sound. Some examples are crash, bang, whoosh.
Words that share a sound sometimes have something in common. If we take, for example, words that have no prefix or suffix and group them according to meaning, some of them will fall into a number of categories. So we find that there is a group of words beginning with /b/ that are about barriers, bulges and bursting, and some other group of /b/ words that are about being banged, beaten, battered, bruised, blistered and bashed. This proportion is, according to Magnus, above the average for other letters.
Another hypothesis states that if a word begins with a particular phoneme, then there is likely to be a number of other words starting with that phoneme that refer to the same thing. An example given by Magnus is if the basic word for 'house' in a given language starts with a /h/, then by clustering, disproportionately many words containing /h/ can be expected to concern housing: hut, home, hovel, habitat...