Comparative method
In linguistics, the comparative method is a technique for studying the development of languages by performing a feature-by-feature comparison of two or more languages with common descent from a shared ancestor and then extrapolating backwards to infer the properties of that ancestor. The comparative method may be contrasted with the method of internal reconstruction in which the internal development of a single language is inferred by the analysis of features within that language. Ordinarily, both methods are used together to reconstruct prehistoric phases of languages; to fill in gaps in the historical record of a language; to discover the development of phonological, morphological and other linguistic systems and to confirm or to refute hypothesised relationships between languages.
The comparative method emerged in the early 19th century with the birth of Indo-European studies, then took a definite scientific approach with the works of the Neogrammarians in the late 19th–early 20th century. Key contributions were made by the Danish scholars Rasmus Rask and Karl Verner, and the German scholar Jacob Grimm. The first linguist to offer reconstructed forms from a proto-language was August Schleicher in his Compendium der vergleichenden Grammatik der indogermanischen Sprachen, originally published in 1861.
Definition
Principles
The aim of the comparative method is to highlight and interpret systematic phonological and semantic correspondences between two or more attested languages. If those correspondences cannot be rationally explained as the result of linguistic universals or language contact, and if they are sufficiently numerous, regular, and systematic that they cannot be dismissed as chance similarities, then it must be assumed that they descend from a single parent language called the 'proto-language'.A sequence of regular sound changes can then be postulated to explain the correspondences between the attested forms, which eventually allows for the reconstruction of a proto-language by the methodical comparison of "linguistic facts" within a generalized system of correspondences.
Relation is considered to be "established beyond a reasonable doubt" if a reconstruction of the common ancestor is feasible.
In some cases, this reconstruction can only be partial, generally because the compared languages are too scarcely attested, the temporal distance between them and their proto-language is too deep, or their internal evolution render many of the sound laws obscure to researchers. In such case, a relation is considered plausible, but uncertain.
Terminology
Descent is defined as transmission across the generations: children learn a language from the parents' generation and, after being influenced by their peers, transmit it to the next generation, and so on. For example, a continuous chain of speakers across the centuries links Vulgar Latin to all of its modern descendants.Two languages are genetically related if they descended from the same ancestor language. For example, Italian and French both come from Latin and therefore belong to the same family, the Romance languages. Having a large component of vocabulary from a certain origin is not sufficient to establish relatedness; for example, heavy borrowing from Arabic into Persian has caused more of the vocabulary of Modern Persian to be from Arabic than from the direct ancestor of Persian, Proto-Indo-Iranian, but Persian remains a member of the Indo-Iranian family and is not considered "related" to Arabic.
However, it is possible for languages to have different degrees of relatedness. English, for example, is related to both German and Russian but is more closely related to the former than to the latter. Although all three languages share a common ancestor, Proto-Indo-European, English and German also share a more recent common ancestor, Proto-Germanic, but Russian does not. Therefore, English and German are considered to belong to a subgroup of Indo-European that Russian does not belong to, the Germanic languages.
The division of related languages into subgroups is accomplished by finding shared linguistic innovations that differentiate them from the parent language. For instance, English and German both exhibit the effects of a collection of sound changes known as Grimm's Law, which Russian was not affected by. The fact that English and German share this innovation is seen as evidence of English and German's more recent common ancestor—since the innovation actually took place within that common ancestor, before English and German diverged into separate languages. On the other hand, shared retentions from the parent language are not sufficient evidence of a sub-group. For example, German and Russian both retain from Proto-Indo-European a contrast between the dative case and the accusative case, which English has lost. However, that similarity between German and Russian is not evidence that German is more closely related to Russian than to English but means only that the innovation in question, the loss of the accusative/dative distinction, happened more recently in English than the divergence of English from German.
Origin and development
In classical antiquity, Romans were aware of the similarities between Greek and Latin, but did not study them systematically. They sometimes explained them mythologically, as the result of Rome being a Greek colony speaking a debased dialect.Even though grammarians of Antiquity had access to other languages around them, they showed little interest in comparing, studying, or just documenting them. Comparison between languages really began after classical antiquity.
Early works
In the 9th or 10th century AD, Yehuda Ibn Quraysh compared the phonology and morphology of Hebrew, Aramaic and Arabic but attributed the resemblance to the Biblical story of Babel, with Abraham, Isaac and Joseph retaining Adam's language, with other languages at various removes becoming more altered from the original Hebrew.In publications of 1647 and 1654, Marcus Zuerius van Boxhorn first described a rigorous methodology for historical linguistic comparisons and proposed the existence of an Indo-European proto-language, which he called "Scythian", unrelated to Hebrew but ancestral to Germanic, Greek, Romance, Persian, Sanskrit, Slavic, Celtic and Baltic languages. The Scythian theory was further developed by Andreas Jäger and William Wotton, who made early forays to reconstruct the primitive common language. In 1710 and 1723, Lambert ten Kate first formulated the regularity of sound laws, introducing among others the term root vowel.
Another early systematic attempt to prove the relationship between two languages on the basis of similarity of grammar and lexicon was made by the Hungarian János Sajnovics in 1770, when he attempted to demonstrate the relationship between Sami and Hungarian. That work was later extended to all Finno-Ugric languages in 1799 by his countryman Samuel Gyarmathi. However, the origin of modern historical linguistics is often traced back to Sir William Jones, an English philologist living in India, who in 1786 made his famous
The Sanscrit language, whatever be its antiquity, is of a wonderful structure; more perfect than the Greek, more copious than the Latin, and more exquisitely refined than either, yet bearing to both of them a stronger affinity, both in the roots of verbs and the forms of grammar, than could possibly have been produced by accident; so strong indeed, that no philologer could examine them all three, without believing them to have sprung from some common source, which, perhaps, no longer exists. There is a similar reason, though not quite so forcible, for supposing that both the Gothick and the Celtick, though blended with a very different idiom, had the same origin with the Sanscrit; and the old Persian might be added to the same family.
Comparative linguistics
The comparative method developed out of attempts to reconstruct the proto-language mentioned by Jones, which he did not name but subsequent linguists have labelled Proto-Indo-European. The first professional comparison between the Indo-European languages that were then known was made by the German linguist Franz Bopp in 1816. He did not attempt a reconstruction but demonstrated that Greek, Latin and Sanskrit shared a common structure and a common lexicon. In 1808, Friedrich Schlegel first stated the importance of using the eldest possible form of a language when trying to prove its relationships; in 1818, Rasmus Christian Rask developed the principle of regular sound-changes to explain his observations of similarities between individual words in the Germanic languages and their cognates in Greek and Jacob Grimm, better known for his Fairy Tales, used the comparative method in Deutsche Grammatik, which attempted to show the development of the Germanic languages from a common origin, which was the first systematic study of diachronic language change.Both Rask and Grimm were unable to explain apparent exceptions to the sound laws that they had discovered. Although Hermann Grassmann explained one of the anomalies with the publication of Grassmann's law in 1862, Karl Verner made a methodological breakthrough in 1875, when he identified a pattern now known as Verner's law, the first sound-law based on comparative evidence showing that a phonological change in one phoneme could depend on other factors within the same word, which are now called conditioning environments.