Principien der Sprachgeschichte (1880) is Hermann Paul's best-known work. In this book, the German literary scholar and linguist argues that although language is a product of human culture and the study of language is therefore best categorised as history, language can most effectively be analysed with methods taken from the natural sciences. Paul develops a system of principles that draws heavily on cognitive and psychological elements in order to account for how language has developed. In 14 chapters he sets out a detailed account of the history of language that includes general observations on the development of language, the consequences of sound change, semantic shift and the divergence of etymologically connected words, and aspects of syntax. He also compares written and spoken language varieties, and the origins of dialects and standard languages.