In this chapter we show how an inheritance hierarchy approach to derivation goes some way in accounting for the distinctions between inflection and derivation that were summarized in Chapter 1 §1.3.3. In §7.1 we discuss derivation as specifically lexeme formation, where the derived lexeme differs from its base at any or all levels of lexical representation: syntactic, semantic, phonological and morphological. Changes at these levels are brought about by inheriting from a Word Formation Rule (WFR) node which encodes syntactic, semantic, phonological and morphological level facts. In §7.2 we show how the traditional category changing, conversion, transposition and category preserving classes of derivation can be expressed as the interplay of inheritance from the base lexical entry node and inheritance from a WFR node. In §7.3 we discuss affix / exponent competition in derivational morphology and demonstrate how it is resolved in Network Morphology by an approach to derivation that makes use of the Paninian principle and base-driven affix selection. Such an approach is reserved for productive derivation only. Semi-productivity, the topic of §7.4, is expressed as either lexical items inheriting from less productive WFR nodes that in turn inherit the productive pattern but override in specific ways; or lexical entries that inherit directly from a productive pattern but override certain aspects of it.
These theories of Russian derivation are incremental improvements of the derivational hierarchy, Network Morphology's way of representing modularisation in morphology.
We also include a toy theory of Shughni expressive morphology as an illustration of head marking category preserving derivation.