Hōri Ngata grew up on the family farm in Waiomatatini and was educated at Te Aute College. He worked as a farmer before serving abroad in the 28th Māori Battalion during the Second World War. After the war he returned to farming in Ruatoria. In 1947 Ngata moved to Mangere Industrial Camp and became Supervisor in 1955. In 1958 he started working as an accountant for the Education Department at Newmarket, Auckland. Ngata was a senior lecturer in Māori at the University of Auckland for nine years and was a licensed interpreter of Māori. As a lecturer of Māori language Ngata saw the scarcity of study resources available for Māori language students and began to compile a dictionary. After his retirement in 1979 Ngata returned to Ruatoria and continued working on the dictionary with an editorial committee, the Komiti ārohi. When Ngata died in 1989, his son Whai continued with his work.
- Phone conversation and correspondence with Whai Ngata, 1 Sept. 1998 and 16 July 2004.
- Ngata, H. M. English-Māori Dictionary. Whanganui-ā-Tara [Wellington], N.Z.: Te Pou Taki Kōrero/Learning Media, 1993. Second Impression, 1994. viii-x.
- English-Māori Dictionary. H. M. Ngata. Whanganui ā Tara/Wellington, N.Z.: Te Pou Taki Kōrero/Learning Media, 1993. Second Impression, 1994.
- An extensive English to Māori dictionary with 14,500 headwords compiled by native speakers including many kaumatua. The dictionary is primarily but not exclusively based on the dialect and idiom of Ngāti Porou.
- Ngata, Whai. "Ngata, Hori Mahue 1919-1989." The Dictionary of New Zealand Biography. Vol. 5. 1941-1960. Auckland; Wellington, N.Z.: Auckland UP; Dept. of Internal Affairs, 2000. 371-372.
- "New English-Māori Dictionary." The Press 17 Nov. 1993: 25.