Panchronic phonology is an approach to historical phonology. Its aim is to formulate generalizations about sound changes that are independent of any particular language or language group.The term 'panchronic' as applied to linguistics goes back at least to Saussure, who uses it to refer to the most general principles, independently of concrete facts. The panchronic program in phonology, however, is associated with the work of André-Georges Haudricourt, especially his seminal articles of 1940 and 1973, and the preliminary synthesis published with Claude Hagège in 1978.Beyond case studies, one of the goals of comparative linguistics is to assemble data that lead to an inventory of the common types of sound change and to an improved understanding of the conditions under which they occur. Panchronic Phonology aims to achieve this: it attempts to formulate generalizations about sound change that are independent of any particular language or language group. Haudricourt (1973) labels such an approach Panchronic Phonology. Panchronic laws are obtained by induction from a typological survey of precise diachronic events whose analysis brings out their common conditions of appearance. In turn, they can be used to shed light on individual historical situations. The Panchronic program in phonology is a development from structural approaches to diachrony. Structural approaches to diachrony study the way in which phonological systems respond to the causes of change. A major source of change is the constant competition between the tendency towards phonological integration and the tendency towards phonetic simplicity. Phonological economy tends to fill structural gaps in phonological systems, and phonetic economy tends to create phonological gaps. Out of the pool of potential changes, the actual direction of evolution observed in a given language depends in part on the state of its phonological system, e.g. – again taking nasality as an example – which nasal phonemes it possesses (among consonants and vowels), which phonotactic constraints they are subject to, and what functional load they have in the system.(in French)