Diachrony and synchrony

Synchrony and diachrony are two complementary viewpoints in linguistic analysis. A synchronic approach (from Ancient Greek: συν- "together" and χρόνος "time") considers a language at a moment in time without taking its history into account. In contrast, a diachronic (from δια- "through" and χρόνος "time") approach, as in historical linguistics, considers the development and evolution of a language through history.^[1]

For example, the study of Middle English—when the subject is temporally limited to a sufficiently homogeneous form—is synchronic focusing on understanding how a given stage in the history of English functions as a whole. The diachronic approach, by contrast, studies language change by comparing the different stages. This latter approach is what surface analysis often relies on, as a given composition may not have appeared synchronously in history. The terms synchrony and diachrony are often associated with historical linguist Ferdinand de Saussure, who considered the synchronic perspective as systematic but argued that language change is too unpredictable to be considered a system.