The phenomenon of loanword adaptation occupies a prominent position in modern phonological literature. The present paper introduces the major theories which deal with this phenomenon as well as presenting the author’s experimental study of online adaptation of Ukrainian word-initial CC consonant clusters illegal in English. In this paper the findings of two experiments are compared and discussed. In the first one 25 native speakers of English imitated Ukrainian words containing word-initial CC consonant clusters absent in English. In the second task a different group of 25 native English speakers were asked to write down the same words in orthographic form. The analysis has shown certain similarities as well as differences between the two s...