Productivity in Diachrony

Productivity refers to the (potential) lexical domain of application of a morphological rule or a grammatical construction. The term has been used with different though related senses, which all somehow evolve around the concepts of regularity, generality , and extensibility . In this chapter, we restrict our discussion to the last use. Originally, productivity was seen as a binary opposition: a derivational rule was either productive or not, depending on the number of new words it was able to create. This discrete approach evolved toward a gradual distinction, which, by the end of the twentieth century, also attracted the syntactic domain into its orbit, drawing on a new conception of grammar in terms of schemas or constructions rather than rules. Although productivity has mainly been studied from a synchronic perspective, the present chapter restricts its scope to diachronic studies, both in the rule‐based and construction‐based traditions. Some of these studies heavily draw on the seminal work by Baayen and colleagues, who set the benchmarks for the quantitative analysis of productivity by means of metrics such as type/token ratio and hapax/token ratio. These are based on type counts performed in large diachronic corpora and supplanted earlier methods based on lemma counts in historical dictionaries. Tracking changes in productivity, however, remains a delicate endeavor. In diachronic research two additional issues arise: (i) the variable composition of diachronic sub‐corpora for different time periods, both in terms of text size and genre; and (ii) the changing token frequency of constructions through time, which challenges the imperative of equal sample size. To circumvent these issues, we have explored different methodological options, and to illustrate the impact of these choices on the results, a small case study is presented featuring the French complex preposition en forme de ‘in the shape of’.