EN
This article presents the section of widespread research devoted to children with a severe delay in speech development; the delay which cannot be linked to any reachable etiological factors – as in case of late bloomers (LB) or children with specific language impairment (SLI). Making an accurate diagnosis, namely distinguishing late bloomers from late talkers before reaching the age of three is currently impossible because of the lack of research reports on LB. Late blooming is the borderline phenomenon of developmental norm, thus it is not in the subject of clinicians’ interest. However, after careful familiarising with the history of research on SLI and numerous reservations about its methodology – our attention was concentrated on late bloomers as a group that is much closer, in terms of development profile (not only linguistic), to SLI-PE (expressive form of this disorder) than younger, properly developing children, who constitute the main comparative group at most research carried out in the world. The study of detailed developmental profile of late bloomers and children with SLI may contribute to the refinement of methods and research tools which are at our disposal and to earlier diagnosis of SLI in the future.