Editing Comparative method (section)

===Comparative linguistics===
The comparative method developed out of attempts to reconstruct the proto-language mentioned by Jones, which he did not name but subsequent linguists have labelled [[Proto-Indo-European]] (PIE). The first professional comparison between the [[Indo-European languages]] that were then known was made by the German linguist [[Franz Bopp]] in 1816. He did not attempt a reconstruction but demonstrated that Greek, Latin and Sanskrit shared a common structure and a common lexicon.<ref>{{harvnb|Szemerényi|1996|pp=5–6}}</ref> In 1808, [[Karl Wilhelm Friedrich von Schlegel|Friedrich Schlegel]] first stated the importance of using the eldest possible form of a language when trying to prove its relationships;<ref>{{harvnb|Szemerényi|1996|p=7}}</ref> in 1818, [[Rasmus Christian Rask]] developed the principle of regular sound-changes to explain his observations of similarities between individual words in the Germanic languages and their cognates in Greek and {{nowrap|Latin.<ref>{{harvnb|Szemerényi|1996|p=17}}</ref>}} [[Jacob Grimm]], better known for his ''[[Grimm's Fairy Tales|Fairy Tales]]'', used the comparative method in ''Deutsche Grammatik'' (published 1819–1837 in four volumes), which attempted to show the development of the [[Germanic languages]] from a common origin, which was the first systematic study of [[Historical linguistics|diachronic]] language change.<ref>{{harvnb|Szemerényi|1996|pp=7–8}}.</ref>

Both Rask and Grimm were unable to explain apparent exceptions to the sound laws that they had discovered. Although [[Hermann Grassmann]] explained one of the anomalies with the publication of [[Grassmann's law]] in 1862,<ref>{{harvnb|Szemerényi|1996|p=19}}.</ref> [[Karl Verner]] made a methodological breakthrough in 1875, when he identified a pattern now known as [[Verner's law]], the first sound-law based on comparative evidence showing that a [[phonology|phonological]] change in one [[phoneme]] could depend on other factors within the same word (such as neighbouring phonemes and the position of the [[stress (linguistics)|accent]]<ref>{{harvnb|Szemerényi|1996|p=20}}.</ref>), which are now called ''conditioning environments''.