System relations in human language have always been in the focus of linguistic studies. Today there exist a number of different but counterparting approaches and principles, models of language phenomena systematization, some of which display polar, while the others – common features. These models reveal different facets of the problem of language categorization itself. The above-mentioned, on the one hand, enriches the general language theory and, on the other hand, gives ground for new perspectives of investigation in the field under study. From this point of view of utmost interest is the prototype theory which is effectively being worked from the end of the 20th century. Being a very particular model of language categorization the prototype theory, however, has rather deep theoretical roots. It is usually related mainly to two polar philosophical principles of categorization – Aristotel’s/Plato’s and Wittgenstein’s. The goal of this paper is, first and foremost, to shed new light on the interaction of the prototype theory and other principles of language categorization, namely invariant/variants hyperonymy/hyponymy, meronymy, centre/periphery. The paper examines how new and already existing approaches benefit from each other particularly in the domain of modern word-formation. Our long-term research carried out on the material of the English, Armenian and Russian languages sustain that in the field of synchronic word-formation the prototype theory may be viewed as a principally new approach to language categorization as in cognitive word-formation it is represented by specific units such as derivational category, derivational-semantic paradigm and typical derivational cluster as well as unique method of categorization, namely, method of derivational prototype modelling.