Sudovian (also known as Yotvingian, Yatvingian, or Jatvingian) is an extinct Western Baltic language of Northeastern Europe. Sudovian was closely related to Old Prussian, it was formerly spoken southwest of the Nemunas river in what is now Lithuania, east of Galindia and north of Yotvingia, and by exiles in East Prussia.
Sudovia and neighboring Galindia were two Baltic tribes or nations mentioned by the Greek geographer Ptolemy in the 2nd century AD as Galíndai and Soudinoí, (, ). Yotvingian and Sudovian are identical in nature, however the Sudovian tribe is commonly grouped with other East Prussian tribes. In reality, the Yotvingian tribe had close linguistic ties to the East Prussian tribes, though were an independent and rather isolated people nonetheless.
After the district was conquered by the Teutonic Knights, the language died out and its speakers were gradually absorbed by German, Lithuanian and Slavic populations.
The language has six grammatical cases: nominative, vocative, accusative, genitive, dative and locative, and a complex morphology with a variety of moods. It was a frontier dialect of Old Baltic, which preserved many archaic features which had been lost in the Middle Baltic group.
Sudovian was very similar to and mutually intelligible with the archaic Old Prussian language, as stated in the introduction to the 1st Old Prussian Catechism (printed in Königsberg - 1545 - the 1st Baltic language book):
Die Sudawen aber wiewol ihre rede etwas nyderiger wissen sich doch inn diese preüßnische sprach : wie sie alhie im Catechismo gedruckt ist auch wol zuschicken und vernemen alle wort - "But the Sudovians, although their speech is somewhat lower, understand this Prussian language, as it is printed in the Catechism, and they express themselves well and understand every word".
There are also some Sudovian language phrases in "Warhafftige Beschreibung der Sudawen auff Samland sambt ihren Bock heyligen und Ceremonien" - True Description of the Sudovians in Samland together with their goat sanctifications and ceremonies - written in the mid-16th century by Hieronymus Meletius.
John Poliander wrote in 1535 about the Sudovians living near Königsberg, Prussia, that 32 villages used Sudini speech in a 6-7 mile stretch of land of the Samland Corner that bears the name of Sudavia. They spoke a language similar to the Old Prussian language, but they used the term gentaras for amber, not the Samlandish (Old Prussian) term. From him we learn that the Sudovians lived secluded from the Samlandish, that they married within their own tribe, and did not allow intermarriage with the neighbouring Prussian population "even if begged". They stubbornly held to their own traditions, and wore finger and ear rings with bronze bells and silver belts. Nothing was imported from abroad, but everything was produced by local craftsmen. Christoph Hartknoch reported in 1684 that there were still Sudovians there.
The Constit. Synod. Evangel. of 1530 contains the following list of deities who were still worshipped by the Sudavians in Samland: "Occopirmus, Sualxtix, Ausschauts, Autrympus, Potrympus, Bardoayts, Piluuytis, Parcunas, Pecols,..." (Hastings, p 488)
Toponyms from N.E. Poland, N.W. Belarus, and Lithuania also preserve words. Sudovian was influenced by the Gothic language, as was Old Prussian. As did other West Baltic dialects, it preserved the nominative singular neuter case ending - absent from Latvian and Lithuanian. In the declension of nouns, five cases are the same as in Old Prussian: nominative, genitive, dative, accusative, vocative. The vocative example "Kails naussen gnigethe." is listed above. The noun declension was very conservative and preserved many archaic features.
The Yotvingian territories of Sudovia and Galindia were later overrun and populated by Slavs around present-day Bia?ystok and Suwa?ki in north-eastern Poland and nearby Hrodna (formerly Grodno) in Belarus. Some elements of Baltic speech are still retained in the Belarus and Ukraine territory, owing to the sparse indigenous populations and resettlements of refugees from Lithuania. The dialect of Zietela (Belarusian , Russian ?, Yiddish Zietil, Polish Zdzi?cio?) was of particular interest. Kazlauskas (1968, p. 285) suggested that the word m?nas ("month") (dative singular mënui) encountered in dialects (Zietela, Lazdijai) and in the writings of Bretk?nas is a remnant of nouns with the stem suffix -s.
Until the 1970s, Yotvingian was chiefly known from toponyms and medieval Russian sources. But in 1978, a monument with Yotvingian writing was discovered by accident. In Belarus, a young man named Vyacheslav Zinov, an amateur collector, bought a book of Catholic prayers from an old man from Novy Dvor village in the depths of Bia?owie?a Forest, which held a small manuscript titled Poga?skie gwary z Narewu ("Pagan Speeches of Narew"). It was written partly in Polish, and partly in an unknown, "pagan" language. Unfortunately, Zinov's parents threw away the book. However, before the manuscript was destroyed, Zinov had made notes of it which he sent to Vilnius University in 1983. Even though Zinov's notes were riddled with errors, it has been proven beyond doubt that the notes are indeed a copy of an authentic Yotvingian text. According to the first person who analyzed the manuscript, Zigmas Zinkevi?ius, this short Yotvingian-Polish dictionary (of just 215 words[Note 1]), Poga?skie gwary z Narewu, appears to have been written by a Catholic priest[Note 2] in order to preach to locals in their mother tongue. Concerning the language, Zinkevi?ius put forth three possible versions: (1) a Yotvingian dialect under a heavy influence of Lithuanian (2) Lithuanian words over a strong Yotvingian substratum (3) the compiler of the dictionary could not tell Lithuanian from Yotvingian clearly, and may have included words from both. The latter version is indirectly supported by the name of the document: "Speeches", rather than "Speech"  Some scholars did not rule out the possibility of forgery, but there are strong indications it was not.