The Word and Paradigm approach to morphology associates lexemes with tables of surface forms for different morphosyntactic property sets. Researchers express their realizational theories, which show how to derive these surface forms, using formalisms such as Network Morphology and Paradigm Function Morphology. The tables of surface forms also lend themselves to a study of the implicative theories, which infer the realizations in some cells of the inflectional system from the realizations of other cells. There is an art to building realizational theories. First, the theories should be correct, that is, they should generate the right surface forms. Second, they should be elegant, which is much harder to capture, but includes the desiderata of simplicity and expressiveness. Without software to test a realizational theory, it is easy to sacrifice correctness for elegance. Therefore, software that takes a realizational theory and generates surface forms is an essential part of any theorist’s toolbox. Discovering implicative rules that connect the cells in an inflectional system is often quite difficult. Some rules are immediately apparent, but others can be subtle. Software that automatically analyzes an entire table of surface forms for many lexemes can help automate the discovery process. Researchers can use Web-based computerized tools to test their realizational theories and to discover implicative rules.
Paradigm Function Morphology (PFM) is an evolving approach to modeling morphological systems in a precise and enlightening way. The fundamental insight of PFM is that words have both content and form and that in the context of an appropriately organized lexicon, a language’s morphology deduces a complex word’s form from its content. PFM is therefore a realizational theory: a language’s grammar and lexicon are assumed to provide a precise characterization of a word’s content, from which the language’s morphology then projects the corresponding form. Morphemes per se have no role in this theory; by contrast, paradigms have the essential role of defining the content that is realized by a language’s morphology. At the core of PFM is the notion of a paradigm function, a formal representation of the relation between a word’s content and its form; the definition of a language’s paradigm function is therefore the definition of its inflectional morphology. Recent elaborations of this idea assume a distinction between content paradigms and form paradigms, which makes it possible to account for a fact that is otherwise irreconcilable with current morphological theory—the fact that the set of morphosyntactic properties that determines a word’s syntax and semantics often differs from the set of properties (some of them morphomic) that determines a word’s inflectional form. Another recent innovation is the assumption that affixes and rules of morphology may be complex in the sense that they may be factored into smaller affixes and rules; the evidence favoring this assumption is manifold.