A radical turning point in the development of popular music occurred after the First World War. Fashionable genres of American popular music have certain influence not only on traditional popular music but also on other music styles – the folklore, spiritual and classical music. At first – at the beginning of the 1920s the influence of American jazz and dance music in Slovakia was in comparison with France and England very rare. But the contact with Vienna and Budapest moves the lifestyle closer to the West, especially among the population of larger cities. At social events in the nature or even in the halls, carnival, pentecostal “rounds” and at weddings, folk songs to the beat of polka, waltz and czardas were played. In salons, theatres and on the boardwalk known melodies of operettas, operas and overtures could be heard. However, in the cafes or in new nightclubs (“bars”), still more and more dances from South and Central America (tango, rumba, samba, and later bossa nova and cha-cha) and from North America (cake walk, foxtrot, ragtime, shimmy, one step, two step and charleston) were heard. Orchestral repertoire gains versatile features and contains tracks of multiple musical styles. There is still more space for improvisation at the expense of the score. The instrumental part of each choir broadens and combined orchestras arise. The original group of dulcimer, brass, salon or spa orchestras is enriched by a set of saxophone and percussion. In the salon and spa orchestras mostly trained musicians played from score papers and in the Roma bands more by ear and feel, they used to improvise. But the musicality of each of them allowed for great flexibility and excellence to reproduce any musical fashion trend. There were quite often Roma as well as non-Roma musicians in the same band. The leading bandmasters in the 1920s were K. Fischer, E. Kozic, F. King, Mozi J., J. Seidl, O. Snopko, J. Stippanitz, J. Weihovsky and others. In Banská Bystrica in the 1930s there performed a universal Roma band composed of B. Kardos, V. Balaz, A. Porteleky a F. Adamsky.
In the 1930s the gap between domestic and world musical development bridged even more. American dances were promoted. By gluing the elements of rhythmics, agogics and articulation of the Argentine Tango with home or folk operetta melodics, harmony and form a Slovak tango emerges. The most important creators of tango in Slovakia in the 1930s are composers Z. Con (Nečakaj ma už nikdy – Do not expect me ever again), P. Cady (Biele margaréty- White daisies, Maria Mariana), G. Dusik (Čo sa mi môže stať- What can happen to me, Marína, Rodný môj kraj, My home region), J. Frank- Zemplinsky (Skôr, než odídeš – Before you leave), R. Hrebenar (Čo srdce nečušíš – Why are you, heart, not silent?), C. Lensky (Nebolo to náhodou – It was not a coincidence), T. Sebo-Martinsky (Zavri oči krásne – Close your beautiful eyes) and others. Then there are lyricists P. Braxatoris, P. Cady, S. Hoza, R. Hrebenar, O. Kausitz, D. Palka and others.
Slovak tangos belong to the jewels of domestic music culture. They are composed sporadically even today, for example, some of them are written by P. Breiner with the band Triango.
The second peculiarity of this period is czardas fox. It is also known as a folk fox (“foxtrot in a folk style”) and fox-polka. It resulted from the merger of the North-American foxtrot dance with elements of the New-Hungarian style. This dance was attributable to the best artists of the New-Hungarian – Roma bands. Later their music performance was copied by other groups and orchestras. The most important composers of the czardas fox were G. Dusik, K. Elbert, E. Generisch, E. Kliment, T. Lengyel, M. Nitriansky, L. Oberth, J. Pihik, J. Pelikan and others.
The foundation of the Czechoslovak Republic caused a boom in Slovak culture by supporting the state language in the literary field, literary-dramatic productions and therefore also in operas and operettas, whose libretto was written in Slovak. But the artistic value and the actual staging of the operettas could not reach the level of opera performances. The operetta as a genre was underestimated, often drawn into nationalist disputes in a multicultural environment in Slovakia. The operetta was pushed out of the opera stage, which was established in 1920, to the alternative scene of folk theatre until it was abolished in 1931. In this area, Slovak music had seen a boom in particular with the arrival of the composer, publisher and a graduate of the Vienna Conservatory Gejza Dusik (1907-1986). His compositional style was based on the European tradition of operas and operettas, but he widely applied American dancing styles in his creation. Looking at him from today’s perspective we can call him a doyen of modern popular music in Slovakia. He wrote many beautiful cantilenas accompanied by sophisticated American rhythms. The most famous of his operettas were Tisíc metrov lásky – A thousand meters of Love (1936), Keď rozkvitne máj -When the May blooms (1938), Modrá ruža – The Blue Rose (1939), Pod cudzou vlajkou – Under a foreign flag (1940), Turecký tabak – Turkish tobacco (1941), Osudný valčík – Fatal Waltz (1943), Tajomný prsteň – Mysterious Ring (1944), Zlatá rybka – Goldfish (1954), Hrnčiarsky bál – Pottery festival (1956), Karneval na Rio Grande – Carnival in Rio Grande (1963), Dvorná lóža – Court loge (1971) and Víno pre Marínu – Wine for Maria (1980). The main librettists of these operettas were P. Braxatoris and O. Kausitz.
Some songs literally acquired the features of folk songs and became hits for decades (Rodný môj kraj – My home region; Čo sa mi môže stať – What can happen to me; Len bez ženy – Only without a woman; Dedinka v údolí – Village in the valley; Vám, jedine Vám- You, only you; Poprosme hviezdy – Let’s ask the stars, Pieseň o rodnej zemi – The song of the home country and others). In these songs he used not only fashionable elements of American dances but as one of the first he also used swing in the operetta Tajomný prsteň – Mysterious Ring (1944). As far as singers were concerned, some of the most important personalities of the then popular music was a tenor, librettist and teacher Stefan Hoza; a tenor, prominent soloist of the Slovak National Theatre and teacher Janko Blaho and finally an actor, director and singer – “bon vivant” Frantisek Kristof Vesely, also known as an actor on the projection screens of older Czech comedies. Bratislava Radio in 1927 first broadcasts the production of Jazz Band led by Frantisek Kral and in 1939 it regularly broadcasts a session on dance music. The phonograph industry had not existed until 1971, when OPUS Co. was established. The first disc with the original two tangos was released outside the territory of Slovakia in 1934. Several Czechoslovak publishing houses of score papers are founded and they contribute in the spread of original Czech and Slovak works, among them e.g. Viktor Holinka – Romanov in Trnava, Robert Janiga and Dusíkovo hudobné nakladateľstvo (Dusik’s music publishing house) in Bratislava, Universum, Ludvik Nerad and Mojmir Urbanek in Prague and Jaroslav Stozicky in Brno. Original creation grews rapidly, so in 1937 there was established a circle of authors of songs and operettas (KAPO) with the goal to promote domestic production.