In this paper I will address the phenomenon of accentuation in prefixed nouns in Slavic, specifically in Russian and Bulgarian, which exhibit both free and mobile stress. I work within the framework of morphological accent, in which each morpheme of the language is encoded with its own accentual properties, either Accented, Post-accented, or Unaccented. The interaction between the accentual properties of constituent morphemes within a word determines the accent of the word.
Prefixes in Slavic are usually unaccented morphemes. Roots, on the other had, are accented, postaccented, or unaccented. The category of words that consist of a prefix and a root, such as Russian proxOd 'passage', and zagAr 'sunburn', displays a certain amount of accentual unpredictability when the accentual properties of constituent morphemes are considered. For example, the root /plat/ pay in Russian is a postaccented root, but when it appears in a prefixed noun such as doplAta 'additional payment', the word is no longer postaccented, but rather accented. Further, the root /kup/ buy, another postaccented root, surfaces as an unaccented root morpheme in the Russian pOdkup 'bribery', where the accent falls on the prefix.
One hypothesis to deal with these phenomena is based on semantic motivations. Some prefixed nouns, as described above, come in accentual pairs that differ both semantically and accentually. For instance, Russian provOd 'the action of the verb provestI/provodIt'' and prOvod 'wire, lead, conductor' demonstrate a pattern found elsewhere among pairs where those nouns denoting an action tend to be accented on the root, while those denoting a physical object tend to be accented on the prefix.