Duke (Nduke, pronounced N-doo-kay) is an Oceanic language now spoken by about 3,000 people on Kolombangara island, Solomon Islands. Duke is an exonymic name (not used by speakers themselves). Endonymic names (used by the speakers themselves) are (Ndughore) and . Dughore is also a name for an area in southwest Kolombangara, Kolei is the general bilateral address term specific to Nduke. A more recent alternative name is 'Kolombangara' (after the name of the island). Social linguistics Oral history in Dughore recounts that the northwest, northeast and southeast of Kolombangara had their own languages, which became extinct when the people of those areas were annihilated in warfare that probably occurred in the early 19th century. The people of the southwest built a series of hill fortresses and survived. At the beginning of the colonial period (about 1900), Duke had about 250 speakers, all concentrated in the southwest. Inter-island exchange with neighbouring island language areas of Vella Lavella, Simbo and Roviana was strong in the latter 19th century, possibly leading to some language borrowing, although marriage remained largely endogamous at that time. In the early twentieth century, colonial rule instituted Roviana as a lingua franca, and the Seventh-day Adventist church, which was widely adopted on Kolombangara, used Bible materials written in Marovo. By the mid-twentieth century marriages to Marovo became numerous and many households are bilingual Duke–Marovo. Roviana, although it ceased to be a regional lingua franca in the 1960s, is still widely understood by Duke speakers. Twentieth-century borrowing from Roviana and Marovo has occurred to a small extent. From the 1960s onward many marriages have taken place across the wider Solomons, leading to mixed-language communities, at the same time that Solomon Pijin has risen to prominence as a national language. As a result, Pijin is a widely used household language on Kolombangara, which in some families has almost fully replaced Duke. Additionally, re-orientation of the economy away from the traditional Oceanic lifestyle has led to less reliance on traditional ecological knowledge and traditional technology, so that many specialist terms have largely been forgotten. The lexical richness of the language is now markedly less among speakers under 40 years old. Ethnologue rates the language as 'vigorous'. Orthography Orthography refers to the spelling system used to write words down. The Nduke alphabet is based on the Latin alphabet. The first systematic orthography was used by A. M. Hocart in 1908 to document a