CAMPBELL, Alexander Duncan. 6.1.1786 (hardly 1789) — 4.4.1857. British (Scottish) Civil Servant in India, interested in Telugu. Served at Madras Civil Service, in 1806 Collector and Magistrate in Bellary (1821 still there), 1816 Member of the Board of Superintendence for College of Fort St. George, 1827 in Tanjore, remained in India at least until 1835, when his son, the future Major-General Alexander C. was born in Madras. Later probably retired, his will is written in Middlesex. Active in Madras Literary Society. The birth year is often given as 1789 and in this time the age of the arrival to India was indeed very low, but independent position as Collecter and Magistrate seems then hardly acceptable.
Publications: A Grammar of the Teloogoo Language, Commonly Termed the Gentoo. 3+25+20+208+19 p. Madras 1816, 2nd ed. 21+31+202+18 p. Madras 1820, 3rd 1849 “Ch. Ph. Brown: “Bhattyam, a crabbled treatise on Telugu grammar, of which Mr. AC had written a translation, tolerably correct” – JRAS 17, 1885, Proc. xvf.).
– A Dictionary of the Teloogoo Language, Commonly Termed the Gentoo, Peculiar to the Hindoos of the North Eastern Provinces of the Indian Peninsula, 4+601+5 p. Madras 1821, 2nd ed. 12+322 p. Madras 1848.
Sources: Not in Br. Biogr. Arch. 1st & 2nd series (but son briefly noted); *Duncan Campbell, Records of clan Campbell in the military service of the honourable East India Company: 1600-1858. London 1925 may be useful, but unavailable to me; stray notes in Internet, books scanned by Google.