Abstract
In this chapter, we will investigate how the picture of interpredictability between paradigm cells changes when considering not only the phonotactic shape of inflected wordforms, but also additional information of a different kind, namely the derivational relatedness of the lexemes involved. In Sect. 6.1, we will use some examples to illustrate the question and to stress the potential relevance of knowing whether two lexemes are ultimately derived from a same base or whether they are formed by means of the same derivational process. We will propose a method to take this information into account and briefly discuss the difference with the standard procedure for entropy computation. We will start from verbal lexemes that ultimately derive from the same base in Sect. 6.2, proposing a working definition of the notion of derivational-inflectional family and showing how our data were coded so as to include a classification in such families in Sect. 6.2.1, briefly providing a qualitative picture of the inflectional behaviour of verbs that belong to the same derivational-inflectional family in Sect. 6.2.2 and presenting our results in Sect. 6.2.3. The same line of reasoning will be followed in Sect. 6.3 for nouns that are formed by means of the same derivational process—i.e., that belong to the same derivational-inflectional series, as defined in Sect. 6.2.1. We will then present in Sect. 6.4 some of the results obtained on the same topic with a different methodology by Bonami and Pellegrini (2022), where the issue of inflectional predictions is framed as a classification problem: a classifier is trained to predict various correlates of the inflectional behaviour of a lexeme from several derivational predictors. We discuss how these results can integrate those of the other sections of this chapter by avoiding some of the problems of the entropy-based approach to the PCFP and by allowing for a quantitative evaluation of the role of many more facets of derivational history. Lastly, in Sect. 6.5, we will discuss the theoretical and methodological implications of our results, also highlighting some problems that we leave to further research.