Critical frequency as an independent variable in grammaticalization

In the frequency literature, it has been argued that high text frequency is the motivating factor in grammaticalization. This claim is questionable for two reasons: linguistic items with high frequency do not necessarily undergo grammaticalization, and it is not unusual for grammaticalization to occur to linguistic items with low frequency. The problems are that neither context nor pragmatic inferring has been taken into serious consideration. The development of new grammatical meaning, the defining feature of grammaticalization, takes place only in contexts in which pragmatic inferring is possible. Therefore, depending on the properties of the contexts, frequency may or may not directly trigger the development of new grammaticalization. The more reliable independent variable and catalyst in grammaticalization is “critical frequency,” i.e., the number of occurrences of a grammaticalizing item in contexts with the similar pragmatic inferring conditions.