(By Balthasar Bickel and Johanna Nichols): "Exponence refers to the number of categories that cumulate into a single formative. The universal default is to express each category by a dedicated formative. These are monoexponential (or separative) formatives. Polyexponential (or cumulative) formatives, i.e. formatives which simultaneously code more than one category, are much rarer. A well-known example is number and case in many Indo-European languages. Marking of case in these languages involves the same formative as marking of number, and it is impossible to identify separate markers of case and number. Thus, in Russian, genitive singular is -i or -a and genitive plural -ej or -ov or -ø, and there is no element in these forms that exclusively expresses case or number. When categories are not cumulated into a single formative, each has its own separate marker. This is so in Turkish, where number is always expressed on nouns by means of the suffix -ler and for each case there is a separate suffix that can combine with -ler, e.g. genitive -in (plural -ler-in), accusative -i (plural -ler-i ), dative -e (plural -ler-e), etc. ❡
Exponence is a purely morphological notion; in particular it is independent of the phonological connection between host and formative. Therefore, monoexponential formatives can combine with any fusion type (see Chapter 20 for the definition of fusion types)."