Uilta (Orok: ульта, also called Ulta, Ujlta, or Orok) is a Tungusic language spoken in the Poronaysky and Nogliksky Administrative Divisions of Sakhalin Oblast, in the Russian Federation, by the Uilta people. The northern Uilta who live along the river of Tym’ and around the village of Val have reindeer herding as one of their traditional occupations. The southern Uilta live along the Poronay near the city of Poronaysk. The language is split in two dialects with very few differences: northern Doronneni and southern Poronaysk.

Uilta is closely related to Nanai, and is classified within the southern branch of the Tungusic languages. Classifications which recognize an intermediate group between the northern and southern branch of Manchu-Tungus classify Uilta (and Nanai) as Central Tungusic. Within Central Tungusic, Glottolog groups Uilta with Ulch as "Ulchaic", and Ulchaic with Nanai as "Central-Western Tungusic", while Oroch, Kilen and Udihe are grouped as "Central-Eastern Tungusic".

Although there has been an increase in the total population of the Uilta there has been a decrease in people who speak Uilta as their mother tongue. The total population of Uiltas was at 200 in the 1989 census of which 44.7, then increased to approximately 300–400 persons. However, the number of native speakers decreased to 25–16 persons.  According to the results of the Russian population census of 2002, Uilta (all who identified themselves as "Oroch with Ulta language", "Orochon with Ulta language", "Uilta", "Ulta", "Ulch with Ulta language" were attributed to Uilta) count 346 people, 201 of whom are urban and 145 of whom are village dwellers. The percentage of 18.5%, which is 64 people pointed that they have a command of their ("Ulta") language, which, mostly, should be considered as a result of increased national consciousness in the post-Soviet period than a reflection of the real situation. In fact, the number of those people with a different degree of command of the Uilta language is less than 10 and the native language of the population is overwhelmingly Russian. Therefore because of the lack of a practical writing system and sufficient official support the Uilta language has become an endangered language.

The language is critically endangered or moribund. According to the 2002 Russian census there were 346 Uilta living in the north-eastern part of Sakhalin, of whom 64 were competent in Uilta. By the 2010 census, that number had dropped to 47. Uilta also live on the island of Hokkaido in Japan, but the number of speakers is uncertain, and certainly small. Yamada (2010) reports 10 active speakers, 16 conditionally bilingual speakers, and 24 passive speakers who can understand with the help of Russian. The article states that "It is highly probable that the number has since decreased further."

Uilta is divided into two dialects, listed as Poronaisk (southern) and Val-Nogliki or Doronneni (northern). The few Uilta speakers in Hokkaido speak the southern dialect. "The distribution of Uilta is closely connected with their half-nomadic lifestyle, which involves reindeer herding as a subsistence economy". The Southern Uilta people stay in the coastal Okhotsk area in spring and summer, and move to the North Sakhalin plains and East Sakhalin mountains during fall and winter. The Northern Uilta people live near the Terpenija Bay and the Poronai River during spring and summer and migrate to the East Sakhalin mountains for autumn and winter.

Matsuura Takeshirō and Ikegami Jirō [ja] were one of the first and most significant scholars in documenting Uilta. Matsuura wrote down about 350 Uilta words in Japanese, including about 200 words with grammatical remarks and short texts. Japanese researcher Nakanome Akira [ja], during the Japanese possession of South Sakhalin, researched the Uilta language and published a small grammar with a glossary of 1000 words. Other researchers who published some work on the Uilta were Magata Hisaharu [ja], Kawamura Hideya [ja], T.I Petrova, A.I Novikova, L.I Sem, and contemporary specialist L.V. Ozolinga. Magata published a substantial volume of dictionaries titled "A Dictionary of the Uilta Language / Uirutago Jiten" in 1981. Others contributing to Uilta scholarship were Ozolinga, who published two substantial dictionaries: one in 2001 with 1200 words, and one in 2003 with 5000 Uilta-Russian entries and 400 Russian-Uilta entries.

Uilta has constrastive vowel length.

Uilta has a (C)V(V)(C) syllable structure. Monosyllabic words always contain either a diphthong or a long vowel, thus no words have the structure *(C)V(C). All consonants may occur both syllable initial and syllable final, however /ɾ/ may not occur word initial, and /m/, /n/ and /l/ are the only consonants that can be word final, with /m/ and /n/ only being permitted to be word final in monosyllabic words.