The repository of concepts available to a human being. The repository constitutes a structured and organised inventory which facilitates categorization and conceptualization. Each concept in the conceptual system can, in principle, be encoded and externalised via language. Concepts encoded in language take a modality-specific format known as a lexical concept. Cognitive linguists assume that language reflects the conceptual system and thus can be employed in order to investigate conceptual organization; they also assume that linguistic organisation which is modified due to use can influence the nature and make-up of the conceptual system.