Kairui-Midiki (also known simply as Midiki or Kairui) is a language of East Timor spoken by 23,000 people in 2015, primarily in Venilale Administrative Post in Baucau, parts of the Viqueque Municipality, and suco Kairui (Manatuto Municipality).^[1]

Kairui-Midiki is closely related to the Waima'a and Naueti languages. These four varieties' level of mutual intelligibility has led some to categorize them as dialects of a single language: Kawaimina.^[2]

Kairui and Midiki were listed separately in the Timor-Leste 2010 Census, but are often considered dialects of a single language, in the literature named Kairui-Midiki.^[3] Kairui is spoken in and around the village of that name in Manatuto, and Midiki is heard in of Lacluta, Liaruca and Venilale. In some districts the names Midiki and Kairui are used interchangeably. And some Midiki speakers near Ossu refer to their language as Osomoko.^[2]

The language is noted for unusual phonological innovations compared to other Timoric languages, including vowel harmony, aspirated and glottalized consonants, and voiceless sonorants in their sound-systems.^[2] A small number of other languages in the greater Timor region also attest voiceless sonorants, aspirated stops, and glottalized consonants. These languages are Waima'a, Naueti, Semau Helong, and Meto. In Midiki, as in Waima'a and Naueti, these consonants only occur at the juncture of a prosodic foot.^[4]