The notion of "strata" was first developed by the Italian linguist Graziadio Isaia Ascoli, and became known in the English-speaking world through the work of two different authors in 1932.
The superstratum case refers to elite invading populations that eventually adopt the language of the native lower classes.
An example would be the Burgundians and Franks in France, who eventually abandoned their Germanic dialects in favor of other Indo-European languages of the Romance branch, profoundly influencing the local speech in the process.
The Gauls lived in the modern French-speaking territory before the arrival of the Romans, namely the invasion of Julius Caesar's army.
[3] It is posited that some structural changes in French were shaped at least in part by Gaulish influence[3] including diachronic sound changes and sandhi phenomena due to the retention of Gaulish phonetic patterns after the adoption of Latin,[4][5][6] calques such as aveugle ("blind", literally without eyes, from Latin ab oculis, which was a calque on the Gaulish word exsops with the same semantic construction as modern French)[7] with other Celtic calques possibly including "oui", the word for yes,[8] while syntactic and morphological effects are also posited.
Relatively clear examples are the Finno-Ugric languages of the Chude and the "Volga Finns" (Merya, Muromian, and Meshcheran): while unattested, their existence has been noted in medieval chronicles, and one or more of them have left substantial influence in the Northern Russian dialects.
By contrast, more contentious cases are the Vasconic substratum theory and Old European hydronymy, which hypothesize large families of substrate languages across western Europe.
[11][15] So can their meaning: words referring to the natural landscape, in particular indigenous fauna and flora, have often been found especially likely to derive from substrate languages.
[14] Although the influence of the prior language when a community speaks, and adopts, a new one may have been informally acknowledged beforehand, the concept was formalized and popularized initially in the late 19th century.
[17] In 1884, Hugo Schuchardt's related but distinct concept of creole languages was used to counter Mueller's view.
In modern historical linguistics, debate persists on the details of how language contact may induce structural changes.
Some linguists contend that Japanese (and Japonic languages in general) consists of an Altaic superstratum projected onto an Austronesian substratum.
[18] Some scholars also argue for the existence of Altaic superstrate influences on varieties of Chinese spoken in Northern China.
For example, early in England's history, Old Norse served as an adstrate, contributing to the lexical structure of Old English.
Modern nations tend to favour a single linguistic variety, often corresponding to the dialect of the capital and other important regions, over others.