Corpus linguistics is the study of language as expressed in samples (corpora) or "real world" text. This method represents a digestive approach to deriving a set of abstract rules by which a natural language is governed or else relates to another language. Originally done by hand, corpora are largely derived by an automated process, which is corrected. The core of a corpus is the derivation of a set of Part-of-speech tags, representing a formal overview of the various types of words and word-relationships in a given language.