Language is a very dynamic and flexible creation which is exposed to constant, almost everyday changes due to the modern way of life, technological developments, and culture mixing. These changes are not limited to the language as a standard but extend to the notion of supradialect, dialect and local dialect. Their impact can mainly be observed in spoken language. Changes in standard language capture the attention of both scientific community and wider public to a large extent due to sociolinguistic factors and the position held by said language variant in society. As a result, changes in native dialects and the issue of disappearance of dialectal variety are pushed into the background. At the same time, the ever-growing decimation and obliteration of local dialects and their value resulted in an increased interest in collecting lexical materials and publishing dialect dictionaries. The city of Dubrovnik also joined the process of raising awareness of the spoken heritage and lexical diversity. Numerous citizens of Dubrovnik, including those who feel like its citizens or simply love Dubrovnik and its cultural and historic heritage, have started to actively publish works on the Dubrovnik dialect. In addition, they started creating educational activities, for both school and TV/radio, all for the purpose of preserving the intangible cultural heritage. However, the goal of raising awareness and of nurturing native dialects, including the Dubrovnik dialect, will not become anything more; it will raise people's awareness of changes and disappearance, but it will not prevent these changes from happening or bring back what was forgotten. Therefore, the question arises as to which extent have the developments in everyday life, and the influence and dominance of the language standard in communication, changed the Dubrovnik dialect, especially in terms of its lexicon. The aim of this thesis was to highlight the abovementioned issues and to provide an overview of the Dubrovnik dialect knowledge testing carried out among the school-age children. The results of the testing showed a decline in knowledge of lexical richness of the native dialect among the younger generation of the city of Dubrovnik. All the data presented in this thesis are based on the findings of the knowledge examinations carried out among fourth- and sixth-grade students. The findings were analysed with respect to the sex, the grade (age) and the family structure/cohabitation with the elderly population. It has been established that there is a difference in knowledge of the Dubrovnik dialect lexicon with respect to the sex and grade, whereas the differences among the respondents with respect to the family structure did not turn out to be significant.