Capell (1962) considered Ngardi, Warlpiri, and Warlmanpa to be dialects of a single language. R. M. W. Dixon (2002) grouped Ngardi together with Warlpiri and Warlmanpa in the Yapa group, but admitted that this was based on limited data. McConvell and Laughren (2004) showed that it was in Ngumbin, a closely related group, and this was followed in Honeyman (2005). However, Bowern (2011) listed it as a more distant Wati language.
McConvell and Laughren (2004) "The Ngumpin-Yapa subgroup". In Claire Bowern & Harold Koch, Australian Languages: Classification and the Comparative Method. Amsterdam/Philadelphia: John Benjamins Publishing Company.