Keywords: folksongs, subdialects, Lejaskurzeme, phonetics, morphology It has been a long time since linguists have spoken about the levelling of subdialects in Latvia, for instance, linguist Jānis Endzelīns already in the middle of the 20th century, when he spoke about the language of the district of Vidzeme said these significant words: “As elsewhere also in Latvia the standard language exterminates subdialects and partly has already exterminated them. There are many areas where it is hard to find a person who speaks only in subdialect.” Therefore, it is important to identify the most important sources of the acquisition of subdialects, which would be useful to all who are interested in subdialectic studies. One of these sources is Latvian folksongs, which vividly preserve the most prominent phonetic and morphological features. The phonetical and morphological features of the subdialects of Lejaskurzeme have been identified in both folksong materials and in later linguistic sources—in the descriptions of Anna Ābele “Par Rucavas izloksni” (On the Rucava Sub-Dialect (1927)), “Rucavas izloksne” (The Rucava Sub-Dialect (1928)), “Gramzdas draudzes izloksne” (The Sub-Dialect of Gramzda Parish (1929)) and also in the description of Emma Valtere “Pērkones izloksne” (The Pērkone Sub-Dialect (1938)) as well as in late 20th century and early 21st century linguistic sources, which allow a comparison between characteristic subdialectical peculiarities and to track their changes over the years. This article analyses the most prominent peculiarities of the subdialects of Lejaskurzeme both in folksongs and in subdialectal sources: in phonetics and morphology. The analysis of the folksongs shows that the treasures of our language are still living; moreover, especially the sources of folklore, including folksongs, are still an actual source of studying subdialects, which, if we use correctly, can reveal grammatical, phonetical, and morphological peculiarities.