EN
The paper is concerned with the processes, mechanisms, and causes of the mutual interaction of segments in connected speech. The factual aspects of these interactional processes and their manifestation are covered by such terms as assimilation, coarticulation, accommodation and transients. There appear to be no objective differences between these terms, i.e. the postulated disparity between linguistic and biomechanical phenomena has not been objectively justified. There are two main mechanisms (models) that attempt to explain the functioning of these phenomena - feature spreading and coproduction. We believe that feature spreading is a more suitable explanatory model, since it covers and describes a wider range of assimilatory cases than coproduction. As far as the causes of these processes are concerned, it seems that the individual types of assimilations may be governed by different principles, and most of the proposed explanations are still hypothetical in nature.