Effects of Singing Folk Songs in Reducing Stress by Foreigner in Korea. The purpose of this study was to investigate whether singing folk songs is associated with changes in levels of immunoglobulin A(IgA) and cortisol in foreigners. The number of migrant workers and foreign students has increased rapidly since the end of the 20th century. Korea is naturally turning into a multicultural society. The foreigners’ life in Korea must be very stressful because of many reasons including culture and language differences. In a naturalistic before-after design, samples of saliva were collected from five foreigners. The results showed that conrtisol concentrations decreased significantly an average of 32%, and IgA concentrations increased an average of 21% after singing, respectively.