Synchrony and diachrony are two complementary viewpoints in linguistic analysis. A synchronic approach – from Ancient Greek: συν- ("together") + χρόνος ("time") – considers a language at a moment in time without taking its history into account. In contrast, a diachronic – from δια- ("through, across") + χρόνος ("time") – approach, as in historical linguistics, considers the development and evolution of a language through history.
For example, a synchronic study of Middle English would focus on understanding how the language functioned at a given stage in its history. A diachronic approach, by contrast, studies language change by comparing different stages at different historical periods. The terms synchrony and diachrony are often associated with the 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.
