Substratum
A substratum or substrate (plural: substrata or substrates) 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 supplanting 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 roughly equal prestige, 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.
In a typical case of substrate interference, a language A occupies a given territory and another language B arrives in the same territory (brought, for example, with migrations of population). Language B then begins to supplant language A: the speakers of language A abandon their own language in favour of B, generally because they believe that it is in their best (e.g. economic, political, cultural, social) interests to do so. During the language shift, however, the receding language A still influences language B (for example, through the transfer of loanwords, place names, or grammatical patterns from A to B).
For example, Gaulish is a substratum of French. The Gauls, a Celtic people, lived in the current French-speaking territory before the arrival of the Romans. Given the cultural, economic and political prestige which Latin enjoyed, the Gauls eventually abandoned their language in favor of Latin, which evolved in this region until eventually it took the form of Modern French. The Gaulish speech disappeared, but it remains detectable in some French words (approximately 150) as well as place-names of Gaulish origin.
Another example is the influence of the now extinct North Germanic Norn language on the Scots dialects of the Shetland and Orkney islands.
In the Arab Middle East and North Africa, colloquial Arabic dialects, most especially Levantine, Egyptian, and Maghreb dialects, often exhibit significant subtrata from other regional Semitic, Iranian, Turkic, and Berber languages as well as colonial European languages due to the regions' long histories of indigenous multiculturalism as well as foreign imperialism.
Linguistic substrata may be difficult to detect, especially if the substrate language and its nearest relatives are extinct. For example, the earliest form of the Germanic languages may have been influenced by a non-Indo-European language, purportedly the source of about one quarter of the most ancient Germanic vocabulary . There are similar arguments for a Sanskrit substrate, and a Greek one.
Typically, Creole languages have multiple substrata, with the actual influence of such languages being indeterminate.
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