Comparative method in the context of Common Slavic

The Caucasian languages comprise a large and extremely varied array of languages spoken by more than ten million people in and around the Caucasus Mountains, which lie between the Black Sea and the Caspian Sea.

Linguistic comparison allows the classification of these languages into several language families, with little or no discernible affinity to each other. However, the languages of the Caucasus are sometimes mistakenly referred to as a family of languages. According to Asya Pereltsvaig, "grammatical differences between the three groups of languages are considerable. [...] These differences force the more conservative historical linguistics to treat the three language families of the Caucasus as unrelated."

Proto-Slavic (abbreviated PSl., PS.; also called Common Slavic or Common Slavonic) is the unattested, reconstructed proto-language of all Slavic languages. It represents Slavic speech approximately from the 2nd millennium BC through the 6th century AD. As with most other proto-languages, no attested writings have been found; scholars have reconstructed the language by applying the comparative method to all the attested Slavic languages and by taking into account other Indo-European languages.

Rapid development of Slavic speech occurred during the Proto-Slavic period, coinciding with the massive expansion of the Slavic-speaking area. Dialectal differentiation occurred early on during this period, but overall linguistic unity and mutual intelligibility continued for several centuries, into the 10th century or later. During this period, many sound changes diffused across the entire area, often uniformly. This makes it inconvenient to maintain the traditional definition of a proto-language as the latest reconstructable common ancestor of a language group, with no dialectal differentiation. (This would necessitate treating all pan-Slavic changes after the 6th century or so as part of the separate histories of the various daughter languages.) Instead, Slavicists typically handle the entire period of dialectally differentiated linguistic unity as Common Slavic.

Proto-Celtic, or Common Celtic, is the reconstructed ancestral proto-language of all known Celtic languages, and a descendant of Proto-Indo-European. It is not attested in writing but has been partly reconstructed through the comparative method. Proto-Celtic is generally thought to have been spoken between 1300 and 800 BC, after which it began to split into different languages. Proto-Celtic is often associated with the Urnfield culture and particularly with the Hallstatt culture. Celtic languages share common features with Italic languages that are not found in other branches of Indo-European, suggesting the possibility of an earlier Italo-Celtic linguistic unity.

Proto-Celtic is currently being reconstructed through the comparative method by relying on later Celtic languages. Though Continental Celtic presents much substantiation for Proto-Celtic phonology, and some for its morphology, recorded material is too scanty to allow a secure reconstruction of syntax, though some complete sentences are recorded in the Continental Gaulish and Celtiberian. So, the main sources for reconstruction come from Insular Celtic languages with the oldest literature found in Old Irish and Middle Welsh, dating back to authors flourishing in the 6th century AD.

Proto-Armenian is the earlier, unattested stage of the Armenian language which has been reconstructed by linguists. As Armenian is the only known language of its branch of the Indo-European languages, the comparative method cannot be used to reconstruct its earlier stages. Instead, a combination of internal and external reconstruction, by reconstructions of Proto-Indo-European and other branches, has allowed linguists to piece together the earlier history of Armenian.

In the tree model of historical linguistics, a proto-language is a postulated ancestral language from which a number of attested languages are believed to have descended by evolution, forming a language family. Proto-languages are usually unattested, or partially attested at best. They are reconstructed by way of the comparative method.

In the family tree metaphor, a proto-language can be called a mother language. Occasionally, the German term Ursprache (pronounced [ˈuːɐ̯ʃpʁaːxə] ; from ur- 'primordial, original' + Sprache 'language') is used instead. It is also sometimes called the common or primitive form of a language (e.g. Common Germanic, Primitive Norse).

The Balto-Slavic languages form a branch of the Indo-European family of languages, traditionally comprising the Baltic and Slavic languages. Baltic and Slavic languages share several linguistic traits not found in any other Indo-European branch, which points to a period of common development and origin.

A Proto-Balto-Slavic language is reconstructable by the comparative method, descending from Proto-Indo-European by means of well-defined sound laws, and from which modern Slavic and Baltic languages descended. One particularly innovative dialect separated from the Balto-Slavic dialect continuum and became ancestral to the Proto-Slavic language, from which all Slavic languages descended.

Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. No direct record of Proto-Indo-European has been discovered; its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. Far more work has gone into reconstructing PIE than any other proto-language, and it is the best understood of all proto-languages of its age. The majority of linguistic work during the 19th century was devoted to the reconstruction of PIE and its daughter languages, and many of the modern techniques of linguistic reconstruction (such as the comparative method) were developed as a result.

PIE is hypothesized to have been spoken as a single language from approximately 4500 BCE to 2500 BCE during the Late Neolithic to Early Bronze Age, though estimates vary by more than a thousand years. According to the prevailing Kurgan hypothesis, the original homeland of the Proto-Indo-Europeans may have been in the Pontic–Caspian steppe of eastern Europe. The linguistic reconstruction of PIE has provided insight into the pastoral culture and patriarchal religion of its speakers. As speakers of Proto-Indo-European became isolated from each other through the Indo-European migrations, the regional dialects of Proto-Indo-European spoken by the various groups diverged, as each dialect underwent shifts in pronunciation (the Indo-European sound laws), morphology, and vocabulary. Over many centuries, these dialects transformed into the known ancient Indo-European languages. From there, further linguistic divergence led to the evolution of their current descendants, the modern Indo-European languages.

In historical linguistics, cognates or lexical cognates are sets of words that have been inherited in direct descent from an etymological ancestor in a common parent language.

Because language change can have radical effects on both the sound and the meaning of a word, cognates may not be obvious, and it often takes rigorous study of historical sources and the application of the comparative method to establish whether lexemes are cognate. It can also happen that words which appear similar, or identical, in different languages, are not cognate.

The Divine Twins are youthful horsemen, either gods or demigods, who serve as rescuers and healers in Proto-Indo-European mythology.

Like other Proto-Indo-European divinities, the Divine Twins are not directly attested by archaeological or written materials, but scholars of comparative mythology and Indo-European studies generally agree on the motifs they have reconstructed by way of the comparative method.

The Proto-Italic language is the ancestor of the Italic languages, most notably Latin and its descendants, the Romance languages. It is not directly attested in writing, but has been reconstructed to some degree through the comparative method. Proto-Italic descended from the earlier Proto-Indo-European language.

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.

The Austronesian languages (/ˌɔːstrəˈniːʒən/ AW-strə-NEE-zhən) are a language family widely spoken throughout Maritime Southeast Asia, parts of Mainland Southeast Asia, Madagascar, the islands of the Pacific Ocean and Taiwan (by Taiwanese indigenous peoples). They are spoken by about 328 million people (4.4% of the world population). This makes it the fifth-largest language family by number of speakers. Major Austronesian languages include Malay (one variant standardized as Indonesian), Javanese, Sundanese, Tagalog (standardized as Filipino), Malagasy and Cebuano. According to some estimates, the family contains 1,257 languages, which is the second most of any language family.

In 1706, the Dutch scholar Adriaan Reland first observed similarities between the languages spoken in the South East Asia Archipelago and by peoples on islands in the Pacific Ocean. In the 19th century, researchers (e.g. Wilhelm von Humboldt, Herman van der Tuuk) started to apply the comparative method to the Austronesian languages. The first extensive study on the history of the phonology was made by the German linguist Otto Dempwolff. It included a reconstruction of the Proto-Austronesian lexicon. The term Austronesian was coined (as German austronesisch) by Wilhelm Schmidt, deriving it from Latin auster "south" and Ancient Greek νῆσος (nêsos "island"), meaning the "Southern Island languages".

Proto-Romance is the result of applying the comparative method to reconstruct the latest common ancestor of the Romance languages. To what extent, if any, such a reconstruction reflects a real état de langue is controversial. The closest real-life counterpart to Proto-Romance would have been a colloquial variety of Late Latin. It would have been part of the complex of vernacular dialects which is popularly, but inaccurately, known as Vulgar Latin.

Linguistic reconstruction is the practice of establishing the features of an unattested ancestor language of one or more given languages. There are two kinds of reconstruction:

• Internal reconstruction uses irregularities in a single language to make inferences about an earlier stage of that language – that is, it is based on evidence from that language alone.
• Comparative reconstruction, usually referred to just as reconstruction, establishes features of the ancestor of two or more related languages, belonging to the same language family, by means of the comparative method. A language reconstructed in this way is often referred to as a proto-language (the common ancestor of all the languages in a given family).

Texts discussing linguistic reconstruction commonly preface reconstructed forms with an asterisk (*) to distinguish them from attested forms.