substrátem
Substrátem, or substratum in English, is a concept in linguistics describing the imprint that a previously spoken language leaves on another language that becomes dominant in a region. The substrate language is often the language of a population that experiences language shift, and its remnants may persist even after the community no longer uses it as a primary means of communication. This concept is distinct from superstratum (the language of a higher-status or ruling group) and adstratum (languages of equal prestige in contact).
Substrátem effects are typically identified in phonology, syntax, morphology, and lexicon. Common manifestations include phonetic patterns
Examples of substrate discussion include debates about Dacian influences on Romanian, Celtic or other pre-Roman layers
Researchers identify substrátem through comparative reconstruction, analysis of structural features not explained by the dominant language