LTKada žiemgalių kalba galutinai išnyko, nustatyti nelengva. Spartus žiemgalių latvėjimas galėjo prasidėti tik XIV a., latgaliams ėmus masiškai kolonizuoti nuo karų ištuštėjusius Lielupės žemumų plotus. Žilbero de Lenua kelionės metu (1413-1414 m.) žiemgališkai dar buvo kalbama. Taigi latviškoje Žiemgalos dalyje žiemgalių kalba galutinai turėjo išnykti greičiausiai ne anksčiau kaip XV a. pabaigoje. Lietuviškoje Žiemgalos dalyje tai galėjo atsitikti ir kiek anksčiau. 1323 m. Gediminas laiške pranciškonų ordino vienuoliams rūpinosi gauti žiemgališkai mokantį kunigą. Taigi XIV a. pirmojoje pusėje čia darbuvo šnekama žiemgališkai. Yra duomenų, kad maždaug po šimtmečio (sprendžiama iš 1426 m. dokumento) žiemgalių sritys, įėjusios į Lietuvos valstybės sudėtį, buvo jau lietuviškos. Taigi čia žiemgalių kalba turėjo išnykti dar XIV a. pabaigoje ar XV a. pradžioje. [Iš straipsnio, p. 85]
ENThe name ofthe Semigallians appeared in the historical sources in the 9th century, so earlier than that of the Lithuanians (in the beginning ofthe 11th century). They were mentioned earliest in the Scandinavian countries (as Seimgaler). Since the beginning of the 12th century the Russian chronicles began mentioning them and from the 13th century the chronicles ofthe German Knights of the Sword mentioned them too. Semigallia (Žiemgala) was understood as the end ofthe Žiemiai (the North) and the Semigallians (žiemgaliai) as the inhabitants of the Žiemiai (the North) land. Only their southern neighbours (most likely Lithuanians) could give them such a name. At present the Latvians call the Semigallian land as "Zemgale" (with the secondary origin "zem-" but not "lziem-") and their inhabitants as "zemgaleši". In Lithuanian it would be "Žemgala" and "žemgaliai". The old land of Semigallia consisted of the areas in the middle part of present-day Latvia (the whole basin ofthe Lielupė river) and in the north of Lithuania approximately as far as the Mūša river. In the west the Semigallians were bordered by the Curonians, in the east by the Selonians and in the north by the Gulf of Riga. The Semigallians, the only ones of all the tribes of Livonia, resisted the Germans most obstinately and for the longest time. The Semigallians struggle for freedom finished after the burning ofthe Sidabre castle in 1290.Tens of thousands of people retreated to Lithuania and others escaped to Kuršas and Vidžemė. In the 14th century, the Lithuanians settled in the southern part of Semigalia and the Latvians settled in the northern (the biggest) part of it. In the first part of the 14th century, the Semigallian language was still spoken in the Lithuanian part of Semigallia. The Semigallian language must have disappeared at the end ofthe 14th century or in the beginning ofthe 15th century. However, the elements of their language are still found in the local dialects of the Mūša river basin and in the Latvian language. [From the publication]