Historical linguistics (also called
diachronic linguistics) is the study of language change. It has five main concerns
Modern historical linguistics dates from the late 18th century and grew out of the earlier discipline of philology, the study of ancient texts and documents, which goes back to antiquity.
At first historical linguistics was comparative linguistics and mainly concerned with establishing language families and the reconstruction of prehistoric languages, using the comparative method and internal reconstruction. The focus was on the well-known Indo-European languages, many of which had long written histories. But since then, significant comparative linguistic work has been done on the Uralic languages, Austronesian languages and various families of Native American languages, among many others. Comparative linguistics is now, however, only a part of a more broadly conceived discipline of historical linguistics. For the Indo-European languages comparative study is now a highly specialised field and most research is being carried out on the subsequent development of these languages, particularly the development of the modern standard varieties.
Initially, all modern linguistics was historical in orientation - even the study of modern dialects involved looking at their origins. But Saussure drew a distinction between synchronic and diachronic linguistics, which is fundamental to the present day organization of the discipline. Primacy is accorded to synchronic linguistics, and diachronic linguistics is defined as the study of successive synchronic stages. Saussure's clear demarcation, however, is now seen to be idealised. In practice, a purely synchronic linguistics is not possible for any period before the invention of the gramophone written records always lag behind speech in reflecting linguistic developments, and in any case are difficult to date accurately before the development of the modern title page. Also, the work of sociolinguists on linguistic variation has shown synchronic states are not uniform the speech habits of older and younger speakers differ in ways which point to language change. Synchronic variation is linguistic change in progress.
