The subject of research in this paper are the adverbial and semi-adverbial phrases (with incomplete lexicalization), which derive from the adhesion of preposition to a full-sense word in the medieval Bulgarian language. The empirical material is systematized on the basis of the preposition involved in the word formation, in view of the adjunct determined by the newly-formed adverbs and on the basis of the lexico-grammatical affiliation of the motivating word. The path of the adverbialization is analyzed in each case and the systematic relations of the newly-formed adverbial unit are tracked.
Key words: Old Bulgarian language, lexical and syntactic word formation, adverbialization.

