Historical linguistics

Historical linguistics, also termed diachronic linguistics, is the scientific study of language change over time.

Quotes

 * Too many comparative historical linguists want to dig up Troy, linguistically speaking. They consider it more important that comparative historical linguists shed light on prehistoric migrations than to shed light on the nature of language change [...] I do not consider comparative historical linguistics a branch of prehistory, and I sincerely believe that if we cared less about dates, maps and trees and more about language change, there’d be more real progress in that field.
 * S.P. Harrison, 2003:23.1. On the limits of the comparative method, in Handbook of Historical linguistics. Quoted from Kazanas, N. (2015). Vedic and Indo-European studies. Aditya Prakashan, page 198