Beyond mere text frequency. Assessing subtle grammaticalization by different quantitative measures. A case study on the Dutch soort construction

Grammaticalization has proven to be an insightful approach to semantic-morphosyntactic change within and across languages. Many studies, however, rely on assessing the large, obvious differences before and after the change. When investigating burgeoning or ongoing grammaticalization processes, it is notably harder to objectively measure the degree of grammaticalization. One approach is to gauge changes in the well-known ‘parameters’ of Lehmann, Hopper, and Himmelmann, but this approach is often qualitatively oriented. Quantitative studies mainly rely either on token frequency of a construction, assuming that grammaticalization is accompanied by a frequency increase, or by tracing the development of two competing constructions, looking at the proportion of their respective token frequencies. In this article, we argue for a wider range of quantitative measures, beyond token frequency, as dependent variables. We will show that these measures can jointly point to subtle ongoing grammaticalization. As a case study, we will focus on Dutch binominals with soort ‘sort’, a core member of the much-discussed sort-kind-type (SKT) construction in the languages of Europe. Based on a large dataset of over 14,000 instances from the period between 1850 and 1999, we investigate quantitatively measurable changes in the construction’s surface behavior (i.e., the gradual loss of the relator van ‘of’ and increasing restrictions on premodification and pluralization, pointing to a process of ‘decategorialization’). In addition, we will also use Gries’s deviation of proportions (DP) to gauge the dispersion of soort, a valuable but under-used metric in quantitative studies of grammaticalization