The present poster presents a systematized and summarized form the process and the main results of a study conducted regarding the nature of the language situation in the city of Plovdiv, in particular the state of the ratio of ethnic and linguistic diversity from the time of the declaration of the city of Plovdiv as the capital of Eastern Roumelia to the present day, with a view to the data of the last fully processed population census of the Republic of Bulgaria in 2011 (a census in the Republic of Bulgaria was also conducted in 2021, but its results are in the process of processing and are expected at the end of 2022). Compared to modern times, the city of Plovdiv is part of the Republic of Bulgaria. The official language today is Bulgarian. Ethnic and linguistic diversity has been preserved over the years, and today, after Bulgarian, the most common languages spoken in the city of Plovdiv are Turkish and Romani. According to the census of 1880, Plovdiv had 24,053 inhabitants: 10,909 Bulgarians, 5,558 Turks, 4,781 Greeks, 865 Gypsies, 806 Armenians, and 1,134 Jews. The numerical superiority of the Bulgarians was preserved and strengthened in the following years, as seen from the census made on January 1, 1885. Plovdiv has 33,442 inhabitants of them: 16,752 Bulgarians, 7,144 Turks, 5,497 Greeks, 2,168 Jews, 1,061 Armenians, etc. This predominance of Bulgarians remains relevant today, as urbanization and globalization have resulted in the emergence of many more minority groups.The study was implemented as part of the activities of the national fundamental project" Plovdiv - from a multilingual and multicultural center of Eastern Rоumelia to the European Capital of Culture". The author expresses his sincere gratitude to the "Scientific Research" Fund at the Ministry of Education and Culture and the "Scientific and Project Activity" Division at Plovdiv University "Paisiy Hilendarski" for the assistance provided.