Phonetic symbols are characters or diacritical marks used to represent the individual sounds (phonemes) of a spoken language. They are used in phonetics and phonology, which are branches of linguistics that study the sounds of language.
The International Phonetic Alphabet (IPA) is the most widely used system of phonetic notation, and it includes a set of standardized symbols that represent the sounds of all languages. These symbols are used to transcribe speech sounds accurately and consistently, and they can be used to show the pronunciation of words in dictionaries, language learning materials, and linguistic research.
For example, the English word "cat" is represented by the phonetic symbols /kæt/ in the IPA.