structural:summarization, structural:reformatting, information:extraction, linguistic:voice_change
Etymology

Etymology studies the history of words: when they entered a language, from what source, and how their form and meaning have changed over time. Words may enter a language in several ways, including being borrowed as loanwords from another language, being derived by combining pre-existing elements in the language, by a hybrid known as phono-semantic matching.

In languages with a long and detailed history, etymology makes use of philology, the study of how words change from culture to culture over time. Etymologists also apply the methods of comparative linguistics to reconstruct information about languages that are too old for any direct information (such as writing) to be known. By analysis of related languages by the comparative method, linguists can make inferences about their shared parent language and its vocabulary. In that way, word roots that can be traced all the way back to the origin of, for instance, the Indo-European language family have been found. Although originating in the philological tradition, much current etymological research is done in language families for which little or no early documentation is available, such as Uralic and Austronesian.