Cognitive linguistics and morphology bear the promise of a happy marriage. Cognitive linguistics provides theoretical concepts and analytical tools for empirical analysis, while morphology offers fertile ground for testing hypotheses and refining core concepts. It is no wonder, then, that numerous contributions to the field of morphology have been couched in cognitive linguistics, and that morphological phenomena have figured prominently in cognitive linguistics. Cognitive linguistics is a family of closely related frameworks that share the idea that language should be analyzed in terms of what is known about the mind and brain from disciplines other than linguistics. Cognitive linguistics furthermore adopts a semiotic perspective, claiming that the raison d’êtreof language is to convey meaning. Another central tenet is the usage-based approach, the idea that grammar emerges through usage, which implies a strong focus on language use in cognitive linguistics. An example of how cognitive linguistics relates morphology to general principles of cognition is the application of general principles of categorization to morphology. Morphological categories are analyzed as radial categories, that is, networks structured around a prototype. Such category networks can be comprised of the allomorphs of a morpheme or be used to model theoretical concepts such as paradigm and inflection class. The radial category is also instrumental in analyzing the meaning of morphological concepts. Rather than assuming abstract invariant meanings for morphemes, cognitive linguistics analyzes the meaning of morphological phenomena through networks of interrelated meanings. The relationships among the nodes in a category network are analyzed in terms of general cognitive processes, such as metaphor, metonymy, and blending. The usage-based approach of cognitive linguistics manifests itself in the strong focus on frequency effects in morphology. It is argued that frequency is an important structuring principle in cognition, and that frequent forms have a privileged status in a morphological paradigm.
Conversion is traditionally viewed as a word-formation technique of forming a word from a formally identical but categorically different word without adding a(n explicit) morphological exponent. Despite its apparent formal simplicity manifested first of all in the sameness of the input and the output, the proper understanding of what exactly happens during conversion, morphosyntactically and semantically alike, is by no means an easy matter even in respect of one language, let alone languages representing different typological groups or subgroups. To determine the linguistic status of conversion and its place among other types of word formation is not a simple matter either, and, paradoxically, it is especially so in the case of the most extensively studied English conversion. The reason for this is that the traditional view of conversion has often been called into question, giving rise to a diversity of interpretations of conversion not only in English but also in a cross-linguistic perspective. Conversion research has gone a long way to explore the mechanism of conversion as a kind of word formation; nevertheless, further research is necessary to understand every detail of this mechanism.