Ideophones are words that evoke an idea in sound, often a vivid impression of certain sensations or sensory perceptions, e.g. sound, movement, color, shape, or action. Ideophones are found in many of the world's languages, though they are claimed to be relatively uncommon in Western languages. In many languages, they are a major lexical class of the same order of magnitude as nouns and verbs: dictionaries of languages like Japanese, Korean, and Zulu list thousands of them. The word class of ideophones is sometimes called phonosemantic to indicate that it is not a grammatical word class in the traditional sense of the word (like 'verb' or 'noun'), but rather a lexical class based on the special relation between form and meaning exhibited by ideophones. In the discipline of linguistics, ideophones have long been overlooked or treated as mysterious words, though a recent surge of interest in sound symbolism, iconicity and linguistic diversity has brought them renewed attention.
An often-cited definition of the notion of ideophone is the following by Clement Martyn Doke
Ideophones evoke sensory events. A well known instance of ideophones are onomatopoeic words – words that imitate the sound (of the event) they refer to. Some ideophones may be derived from onomatopoeic notions. A case in point is the English ideophonic verb to tinkle, which imitates a brief metallic sound. In many languages, however, ideophones go far beyond onomatopoeia in imitating many things beyond sound. For instance, in Gbaya, kpuk 'a rap on the door' may be onomatopoeic, but other ideophones depict motion and visual scenes: loɓoto-loɓoto 'large animals plodding through mud', kiláŋ-kiláŋ 'in a zigzagging motion', pɛɗɛŋ-pɛɗɛŋ 'razor sharp'.
Ideophones are often characterized as iconic or sound-symbolic words, meaning that there can be a resemblance between their form and their meaning. For instance, in West-African languages, voiced consonants and low tone in ideophones are often connected to large and heavy meanings, whereas voiceless consonants and high tones tend to relate to small and light things.Reduplication figures quite prominently in ideophones, often conveying a sense of repetition or plurality present in the evoked event. The iconicity of ideophones is shown by the fact that people can guess the meanings of ideophones from various languages at a level above chance. However, not everything about the form of ideophones directly relates to their meaning; as conventionalized words, they contain arbitrary, language-specific phonemes just like other parts of the vocabulary.