Picard's methodology has three stages: establishing the sound correspondences between a source language (such as Proto-Algonkian) and a target language (such as Arapaho); exploiting the concept of naturalness in phonological change to the fullest in order to construct working hypotheses as to what the most likely historical processes could have been, and to determine in a nonarbitrary fashion which processes could have taken place simultaneously; and ordering these processes in accordance with the various feeding, bleeding, counterfeeding, and counterbleeding relations that exist between a great many pairs of diachronic processes.