Adstratum
An adstratum or adstrate (plural: adstrata or adstrates) refers to a language which is equal in prestige to another. Generally the term is used only when speaking about languages in a particular country or geopolitical region. For example, early in England's history, Old English and Norse had an adstratal relationship.
The phenomenon is relatively rare today, since modern nations generally have only one dominant language (often corresponding to the dialect of the capital). In India, where dozens of languages are widespread, many could be said to share an adstratal relationship, although Hindi is certainly dominant in North India. A more accurate example would be the situation in Belgium, where the French and Dutch languages have roughly the same status, and could justifiably be called adstrates.
The term is also used to identify systematic influences or a layer of borrowings in a given language from another language where the two languages coexist as separate entities. Many modern languages have an appreciable adstratum from English. The Neo-Latin and Neo-Greek coinages adopted by European languages (and now, languages worldwide) to describe scientific topics (anatomy, medicine, botany, zoology, all the '-ology' words, etc.) can also justifiably be called adstrata. Another example is found in the Spanish and Portuguese languages, which contain a heavy Semitic (particularly Arabic) adstratum.
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