It is a generally accepted view in studies dealing with Hungarian sound history literature that the old Hungarian language did not favour initial consonant clusters, a feature inherited from Finno-Ugric. Much has been written about the disappearance of such initial clusters in loanwords. However, the toponymic corpus researched by the author clearly shows that the other side of the question is also worth examining. A great number of words with initial consonant clusters can be collected from the early attestations of the Hungarian language. Therefore, the present author’s chief aim has been to reveal the phonological features of these words in his work. At the same time, he also attempts to reinterpret some traditional ways of solution that have been suggested so far, because the large number of the words with initial consonant clusters also raises the question why these problematic sound combinations disappeared after all later in many cases.

Therefore the author not only describes and analyses initial consonant clusters but also verifies the phonological evidence provided by place names. So far, not too much attention has been paid to this aspect of toponyms in Hungarian phonological studies. On the one hand, place names can provide more data from the earlier periods than common words, on the other hand they afford new perspectives for research on of the Hungarian language. As place names are attached to different locations they can be observed not only in themselves but also in their relationships to their environment. and through this real language context they can be contextualized. As a consequence, it is easier to ascertain their immediate etymon and to determine the time of their emergence, moreover, in certain cases the curve of prevalence of phonetic changes in a certain area can be described. With these aspects in mind the author aims to prove that place names with their linguistic changes convey more information than common words. This is the conclusion drawn by the author after the analysis of more than 900 place names with initial consonant clusters.