page_title: Historical linguistics
section_title: Sub-fields of study
hierarchical_section_title: Historical linguistics / Sub-fields of study
context_page_description: Historical linguistics, also termed diachronic linguistics, is the scientific study of language change over time. Principal concerns of historical linguistics include:
  to describe and account for observed changes in particular languages
  to reconstruct the pre-history of languages and to determine their relatedness, grouping them into language families
  to develop general theories about how and why language changes
  to describe the history of speech communities
  to study the history of words, i.e. etymology
  Historical linguistics is founded on the Uniformitarian Principle, which is defined by linguist Donald Ringe as followed:
  Unless we can demonstrate significant changes in the conditions of language acquisition and use between some time in the unobservable past and the present, we must assume that the same types and distributions of structures, variation, changes, etc. existed at that time in the past as in the present.
caption: Classification of Indo-European languages. Red: Extinct languages. White: categories or unattested proto-languages. Left half: centum languages; right half: satem languages