It is common for the grammar of languages to mark certain conceptual categories. Inasmuch as language is a part of cognition in general-and a major part at that-conceptual categories marked by the grammars of languages are important in understanding the nature of cognitive categories in general.
- Lakoff (1987), Pag. 91

Conceptual categories are not merely characterized in terms of objective properties of category members. They differ in two respects: - Human conceptual categories have properties that are, at least in part, determined by the bodily nature of the people doing the categorizing rather than solely by the properties of category members. - Human conceptual categories have properties that are a result of imaginative processes (metaphor, metonymy, mental imagery) that do not mirror nature.
- Lakoff (1987), Pag. 371