The term substrate (or substratum) is frequently encountered in discussions of linguistic development. According to Thomason and Kaufman (1988:38), “substratum interference is a subtype of interference that results from imperfect group learning during a process of language shift.” They further state (1988:39) that “[substratum interference] does not begin with vocabulary but with sounds and syntax and sometimes includes morphology well before words.” However, it is oft…