When a verb is borrowed into Russian, it must adapt to the Russian
aspectual system. The borrowed verb takes on the functions of one of the
two aspects and often (but not always) forms a corresponding verb in
the other aspect, forming what is called an aspectual pair, one
imperfective and one perfective verb sharing meaning but differing in
aspect. Most new verbs in Russian are borrowed from languages that do
not have the imperfective–perfective aspectual opposition. For this
reason, borrowed verbs give us an interesting opportunity to study the
mechanisms behind the formation of aspectual pairs. This observational
study consists of 248 unprefixed verbs ending on -ovat′ or -evat′,
borrowed during the twentieth century. The material was gathered from
the Russian National Corpus (RNC), from the online dictionary
Wiktionary, and from seven printed dictionaries from the twentieth and
twenty-first centuries. The results of the study are that the most
common method to form aspectual pairs is prefixation; the most common
aspectual prefixes are za-, s-, pro- and ot-; the choice of prefix is
influenced by the meaning of the verb; and that the overlap in meaning
between prefix and verb is especially visible in verbs with spatial
meaning.