Comparative linguistics in the context of "Indo-European migrations"

Historical linguistics, also known as diachronic linguistics, is the scientific study of how languages change over time. It seeks to understand the nature and causes of linguistic change and to trace the evolution of languages. Historical linguistics involves several key areas of study, including the reconstruction of ancestral languages, the classification of languages into families, (comparative linguistics) and the analysis of the cultural and social influences on language development.

This field is grounded in the uniformitarian principle, which posits that the processes of language change observed today were also at work in the past, unless there is clear evidence to suggest otherwise. Historical linguists aim to describe and explain changes in individual languages, explore the history of speech communities, and study the origins and meanings of words (etymology).

Paul Jules Antoine Meillet (French: [ɑ̃twan mɛjɛ]; 11 November 1866 – 21 September 1936) was one of the most important French linguists of the early 20th century. He began his studies at the Sorbonne University, where he was influenced by Michel Bréal, the Swiss linguist Ferdinand de Saussure, and the members of the L'Année sociologique. In 1890 he was part of a research trip to the Caucasus, where he studied the Armenian language. After his return, de Saussure had gone back to Geneva, so Meillet continued the series of lectures on comparative linguistics that de Saussure had given.

In 1897 Meillet completed his doctorate, Research on the Use of the Genitive-Accusative in Old Slavonic. In 1902 he took a chair in Armenian at the Institut national des langues et civilisations orientales and took under his wing Hrachia Adjarian, who would become the founder of modern Armenian dialectology. In 1905 Meillet was elected to the Collège de France, where he taught on the history and structure of Indo-European languages. One of his most-quoted statements is that "anyone wishing to hear how Indo-Europeans spoke should come and listen to a Lithuanian peasant." He worked closely with linguists Paul Pelliot and Robert Gauthiot.

Etymology (/ˌɛtɪˈmɒlədʒi/ ET-ih-MOL-ə-jee) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. Most directly tied to historical linguistics, philology, and semiotics, it additionally draws upon comparative semantics, morphology, pragmatics, and phonetics in order to attempt a comprehensive and chronological catalogue of all meanings and changes that a word (and its related parts) carries throughout its history. The origin of any particular word is also known as its etymology.

For languages with a long written history, etymologists make use of texts, particularly texts about the language itself, to gather knowledge about how words were used during earlier periods, how they developed in meaning and form, or when and how they entered the language. Etymologists also apply the methods of comparative linguistics to reconstruct information about forms that are too old for any direct information to be available. By analyzing related languages with a technique known as the comparative method, linguists can make inferences about their shared parent language and its vocabulary. In this way, word roots in many European languages, for example, can be traced back to the origin of the Indo-European language family.

Philology (from Ancient Greek φιλολογία (philología) 'love of word') is the study of language in oral and written historical sources. It is the intersection of textual criticism, literary criticism, history, and linguistics with strong ties to etymology. Philology is also defined as the study of literary texts and oral and written records, the establishment of their authenticity and their original form, and the determination of their meaning. A person who pursues this kind of study is known as a philologist. In older usage, especially British, philology is more general, covering comparative and historical linguistics.

Classical philology studies classical languages. Classical philology principally originated from the Library of Pergamum and the Library of Alexandria around the fourth century BC, and was continued by the Ancient Greeks and then the Romans throughout the Roman and Byzantine Empire. It was eventually resumed by European scholars of the Renaissance, where it was soon joined by philologies of other European (Romance, Germanic, Celtic, Slavic, etc.), Asian (Arabic, Persian, Sanskrit, Chinese, etc.), and African (Egyptian, etc.) languages. Indo-European studies involve the comparative philology of all Indo-European languages.

In historical linguistics, the tree model (also Stammbaum, genetic, or cladistic model) is a model of the evolution of languages analogous to the concept of a family tree, particularly a phylogenetic tree in the biological evolution of species. As with species, each language is assumed to have evolved from a single parent or "mother" language, with languages that share a common ancestor belonging to the same language family.

Popularized by the German linguist August Schleicher in 1853, the tree model has been a common method of describing genetic relationships between languages since the first attempts to do so. It is central to the field of comparative linguistics, which involves using evidence from known languages and observed rules of language feature evolution to identify and describe the hypothetical proto-languages ancestral to each language family, such as Proto-Indo-European and the Indo-European languages. However, this is largely a theoretical, qualitative pursuit, and linguists have always emphasized the inherent limitations of the tree model due to the large role played by horizontal transmission in language evolution, ranging from loanwords to creole languages that have multiple mother languages. The wave model was developed in 1872 by Schleicher's student Johannes Schmidt as an alternative to the tree model that incorporates horizontal transmission.

Louis Trolle Hjelmslev (Danish: [ˈjelˀmsle̝w]; 3 October 1899 – 30 May 1965) was a Danish linguist whose ideas formed the basis of the Copenhagen School of linguistics. Born into an academic family (his father was the mathematician Johannes Hjelmslev), Hjelmslev studied comparative linguistics in Copenhagen, Prague and Paris (with Antoine Meillet and Joseph Vendryes, among others). In 1931, he founded the Cercle Linguistique de Copenhague. Together with Hans Jørgen Uldall he developed a structuralist theory of language which he called glossematics, which further developed the semiotic theory of Ferdinand de Saussure. Glossematics as a theory of language is characterized by a high degree of formalism. It is interested in describing the formal and semantic characteristics of language in separation from sociology, psychology or neurobiology, and has a high degree of logical rigour. Hjelmslev regarded linguistics – or glossematics – as a formal science. He was a pioneer of formal linguistics. Hjelmslev's theory became widely influential in structural and functional grammar, and in semiotics.

The Altaic (/ælˈteɪ.ɪk/ ) languages are a sprachbund and rejected proposed language family comprising the Turkic, Mongolic and Tungusic language families, with some linguists having included the Koreanic and Japonic families. The proposed Altaic language family is no longer considered valid, as linguistic similarities among Turkic, Mongolic, and Tungusic languages are better explained by areal convergence within a convergence zone rather than by a shared genetic lineage, a phenomenon observed cross-linguistically in diverse language families worldwide.

These languages share agglutinative morphology, head-final word order and some vocabulary. The once-popular theory attributing these similarities to a common ancestry has long been rejected by most comparative linguists in favor of language contact, although it continues to be supported by a small but stable scholarly minority. Like the Uralic language family, which is named after the Ural Mountains, the group is named after the Altai mountain range in the center of Asia.