Two eye-tracking experiments in the Visual World paradigm compared how monolingual Russian (Experiment 1) and heritage Russian-English bilingual (Experiment 2) listeners process contrastiveness online in Russian. Materials were color adjective-noun phrases embedded into the split-constituent construction Krasnuju polozite zvezdovku..."Red put star..." whose inherent contrastiveness results from integration of multiple sources of information, i.e., word order, prosody and visual context. The results showed that while monolinguals rapidly used word order and visual context (but not contrastive prosody) to compute the contrast set even before the noun appeared in speech, heritage Russian bilinguals were very slow and took notice of multiple sources of information only when the lexical identity of the noun made the task superfluous. These results are similar to slowed processing reported in the literature for L2 learners. It is hypothesized that this slowdown in HL processing is due to cascading effects of covert competition between the two languages that starts at the level of spoken word recognition and culminates at the interfaces and, with time, it may become a major contributing force to heritage language attrition.