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.