This study investigates possessives and modified definite DPs in a corpus of heritage Norwegian spoken in the US. Both constructions involve variation in Norwegian – two word orders for possessives (pre- and postnominal) and two exponents of definiteness (a prenominal determiner and a suffix) – while English only has one of these options. The findings show that a large majority of the heritage speakers overuse the structures that are maximally different from English structures, i.e., postnominal possessors and single suffixal definiteness marking. We argue that their production pattern is the result of cross-linguistic overcorrection (CLO). In addition, a small group of the heritage speakers show signs of cross-linguistic influence (CLI) and overuse the English-like structures in both constructions. These speakers also have a slightly lower proficiency in the heritage language. Our findings are discussed in terms of previous research on monolingual and Norwegian–English bilingual children.

Cross-linguistic influence (CLI) has been claimed to occur under the conditions of structural overlap, interfacing, syntactic complexity and language dominance. This study tested adjective placement in the Italian of 19 adult German–Italian simultaneous bilinguals, comparing naturalistic and experimental data. The results show no CLI from German, although the conditions for CLI are given. Instead, bilingual adults tend to overuse a structure that is unique to Italian, unlike bilingual children in previous studies. However, they do so only in the experimental data. In order to account for this, I introduce the concept of cross-linguistic overcorrection in contrast to cross-linguistic influence.