Foreward For centuries people have been fascinated by language,and vari- ous scholars have devised theories that attempt to explain how lan- guage works.For just as long,people have been fascinated by the mind and have wondered how it does all the things it does.As lan- guage is a product of the human mind,an understanding of one should help to understand the other. Some early investigators of language believed that their work would shed light on the workings of both language and the mind.But during the past several decades most of the scholars in the field of lin- guistics have treated language as an abstract symbol system without any apparent relationship to actual human beings,even while some of them have professed an interest in the mind. In my research I have tried to understand language as first and foremost a mental system,in the hope of learning more about the na- ture of language as well as the nature of the mind.In order to treat language as a mental system it is necessary to apply certain criteria that are not normally considered in linguistics.These added require- ments make greater demands on the investigator,and with their use we develop a new kind of linguistics,wbich I call 'neurocognitive linguistics'.These criteria are requirements that a theory must meet in order to be considered realistic from a neurocognitive point of view. The basic criterion is that of operational plausibility:The lin- 3