The article deals with the analysis of idioms. The analysis without context considerably narrows the possibilities of the researcher. In speech and text idioms undergo through various modifications. In the terms of bookish idioms, we had concerns about their ability to be easily modified as most of them belong to outdated vocabulary or have obsolete word in their structure. The article presents the study of main research papers as well as the achievements made by internationally well-known scholars in the field of linguistics, also the study presents a short literature review on the problem of modifications of idioms. Secondly, there is an analysis of the experiment provided among students of Kazan Federal University Russian native speakers majoring at English. The experiment aimed at estimating capability of bookish idioms of English and Russian to undergo modifications. The materials of the study may be useful worldwide by educators and researchers involved in professional linguistic research and training.