This is a survey article that brings together some more familiar patterns in the acquisition of Russian (by monolingual speakers) and lesser known ones, reflecting the acquisition and maintenance of Russian in the context of another dominant language ‐ in this case, American English. Assuming a critical distinction between two types of acquisition, the acquisition of language that results in complete, full native speaker competency (regardless of whether a particular speaker represents the standard, educated, variety of L1, or any other of its varieties), and the acquisition interrupted, in childhood, by the switch to another language as dominant, the former will be referred to as uninterrupted acquisition, the latter as incomplete acquisition. Of these two, uninterrupted acquisition is the one that is standardly pursued and discussed in L1 acquisition studies. Incomplete acquisition, which results in the linguistic profile of a heritage speaker, has gone mostly unnoticed, for a number of reasons. To name just a few: heritage speakers often have passive language skills only, which makes it hard to assess their language competence. Heritage speakers are often mistaken for unbalanced bilinguals, and as such considered desirable subjects for bilingualism research. Lumped together with other types of language attrition and loss, the language of heritage speakers has chiefly been the province of sociolinguistic studies, and it is often hard to make two separate subfields within linguistics talk to one another. In the meantime, heritage speakers may well be an important missing piece that would enrich the picture of L1 acquisition that we are trying to create.