This article introduces, illustrates, and discusses a method for measuring the attrition of communicative competence using data from spontaneous, freestyle, multiperson conversations. The illustration is based on speech production data of Spanish L3 subjects' from Ghana. The method involves the creation of a multiple-factor (composite) index using defined temporal variables, frequency counts of selected verbal behaviors, and grammatical information; it can be used to measure either the rate of attrition or its reverse, which, for lack of a better term, is called the “accumulation of competence.”