July 8, 1840|
|Died||September 20, 1916
|Main interests||Indo-European studies, Baltic and Slavic languages|
Leskien was born in Kiel. He studied philology at the universities of Kiel and Leipzig, receiving his doctorate from the latter in 1864. He taught Latin and Ancient Greek at the Thomasschule zu Leipzig from 1864-1866. In 1866 he began studying comparative linguistics under August Schleicher at the University of Jena. He completed his habilitation in 1867 and went on to lecture at the University of Göttingen. He was appointed as the außerordentlicher professor of comparative linguistics and Sanskrit at Jena in 1868. Two years later he was named as the außerordentlicher professor of Slavic philology at the University of Leipzig. He was promoted to full professorship in 1876 and remained in the position until 1915. Leskien was a founding member of the journal Archiv für slavische Philologie. He died in Leipzig.
Research, writings and thought 
Leskien was a central figure in the group of linguists at Leipzig who later became known as the Neogrammarians. The group strove to approach linguistics in a scientific manner; Leskien formulated their main doctrine, namely that phonetic laws have no exceptions (Ausnahmslosigkeit der Lautgesetze). Leskien's hypothesis was that phonetic shifts do not occur randomly or haphazardly, but instead are the product of directly observable conditions. Among the students that Leskien taught are: Jan Niecisław Baudouin de Courtenay, Ferdinand de Saussure, Leonard Bloomfield, Nikolai Trubetzkoy, Karl Verner and Adolf Noreen. Thus Leskien can be seen as a key founder of modern comparative linguistics, particularly in the fields of Baltic and Slavic languages.
In his 1881 essay 'Die Quantitätsverhältnisse im Auslaut des Litauischen', Leskien formulated Leskien's Law, a sound law devised to describe a particular aspect of sound change in the Lithuanian language. According to this law long vowels, along with the diphthongs ie and ou, with an acute intonation are shortened in the final syllable of a word. Leskien is also the author of Handbuch der altbulgarischen sprache, a guide to Old Church Slavonic. Although superseded in places by more recent studies, the book is still in print and remains in use by scholars to the present day.
- Walther Killy and Rudolf Vierhaus (eds.) (1997). Deutsche Biographische Enzyklopädie (DBE). Band 6: Kogel – Maxsein. München (u. a.): K.G. Saur. p. 342.
- Wilhelm Streitberg: "August Leskien". In: Indogermanisches Jahrbuch I (1913). p. 216–218.
- Wilhelm Streitberg: "August Leskien". In: Indogermanisches Jahrbuch VII (1919). p. 138–143.
- Harald Wiese: Eine Zeitreise zu den Ursprüngen unserer Sprache. Wie die Indogermanistik unsere Wörter erklärt, Logos Verlag Berlin, 2007.