Xeseco:ni (or Xeseco:ni-Sâmyaren) is a language family indigenous to southern Rexanas. It is divided into two branches: the Sâmyaren branch, consisting entirely of Saimiar and its daughter languages, and the non-Sâmyaren branch representing the rest of the family. Saimiar itself is a fairly divergent language within the family, having been long-isolated from other Xeseco:ni languages by the migration of the Saimi south into Dvanashi in prehistorical times. Other Xeseco:ni languages include Uklebni, Stozesh, and Chgarti.

The Xeseco:ni family is characterized by a high degree of agglutinative morphology on both nouns and verbs, morphological and in some cases syntactic ergativity, a morphological case system of 6-9 noun cases, and a tendency towards complicated consonant clusters. Most Xeseco:ni languages also exhibit a two-way masculine/feminine gender system on nouns and an ejective stop series, although Saimiar has lost both of these features.