Substratum

In linguistics, a stratum (Latin for "layer") or strate is a language that influences, or is influenced by another through contact. A substratum or substrate is a language which has lower power or prestige than another, while a superstratum or superstrate is the language that has higher power or prestige. Both substratum and superstratum languages influence each other, but in different ways. An adstratum or adstrate refers to a language that is in contact with another language in a neighbor population without having identifiably higher or lower prestige. The notion of "strata" has first been developed by the Italian linguist Graziadio Isaia Ascoli (1829–1907), and became known in the English-speaking world by two different authors in 1932.

Thus, both terms refer to a situation where an intrusive language establishes itself in the territory of another, typically as the result of migration. Whether the superstratum case (the local language persists and the intrusive language disappears) or the substratum one (the local language disappears and the intrusive language persists) applies will normally only be evident after several generations, during which the intrusive language exists within a diaspora culture. In order for the intrusive language to persist (substratum case), the immigrant population will either need to take the position of a political elite or immigrate in significant numbers relative to the local population (i. e., the intrusion qualifies as an invasion or colonisation; an example would be the Roman Empire giving rise to Romance languages outside of Italy, displacing Gaulish and many other languages). The superstratum case refers to migratory elite populations which eventually adopt the local language (an example would be the Burgundians and Franks in France, who eventually abandoned their Germanic dialects in favor of Romance).

A substratum (plural: substrata) or substrate is a language that influences an intrusive language that supplants it. The term is also used of substrate interference; i.e. the influence the substratum language exerts on the replacing language. According to some classifications, this is one of three main types of linguistic interference: substratum interference differs from both adstratum, which involves no language replacement but rather mutual borrowing between languages of equal "value", and superstratum, which refers to the influence a socially dominating language has on another, receding language that might eventually be relegated to the status of a substratum language.

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