The type-token distinction is a fundamental concept in linguistics, philosophy of language, and semiotics. It refers to the differentiation between linguistic units in terms of their general form or concept (type) and specific instances or occurrences in speech or writing (tokens).

Types are abstract linguistic entities that represent general categories of words or expressions. They are mental constructs that encompass the shared characteristics and meaning associated with a particular word or phrase. For example, the word "apple" is a type that represents the general concept of a fruit, regardless of its specific occurrence in a sentence.

Tokens, on the other hand, are concrete, observable instances of linguistic elements in actual use. They are the specific occurrences of words or expressions in context. In written language, tokens are the individual words, sentences, or paragraphs that we read. In spoken language, tokens are the words and sentences we hear.

The type-token distinction is crucial for understanding language variability and the way language functions in communication. While types represent linguistic knowledge and the mental lexicon shared among language users, tokens are the realizations of this knowledge in everyday language use. Linguistic analysis often involves studying both types and tokens to gain insights into language structure, meaning, and usage patterns.

In addition to linguistics, the type-token distinction is also relevant in areas such as computational linguistics, where it is used in natural language processing tasks, and in philosophy of language, where it is employed to explore questions about language ontology and meaning.