 His classification was later improved by .Their classification is known as Jaunius–Salys or traditional classification when compared to the newer classification of Zigmas Zinkevičius and .In 1891–1898, he wrote and published descriptions of dialects in six uyezds – Ukmergė in 1890, Kaunas in 1891, Raseiniai in 1892, Zarasai in 1894, Šiauliai in 1895, Panevėžys in 1897 and 1898.