ref
From various Chinese surnames, including 吳/ 吴 (Cantonese: ng4, Hakka: Ǹg) and 伍 (Cantonese: ng5, Hakka: Ńg) via Cantonese or Hakka, and 黃/ 黄 (N̂g) and 阮 (Ńg) via Min Nan.