The online Yolngu Matha dictionary defines madarrpa as a clan-nation and language affiliated with dhuwala'mirri N199. Schebeck describes Madarrpa as a dialect of Dhuwala N199 but reports that some people now use Ritharrngu N104 and Burarra (see N135) (2001:15, 18). Wilkinson lists Madarrpa under Dhuwala N199 and Ritharr?u N104 (1991:13). Heath lists Ritharrngu N104, Dhay'yi N118 and Duwaya N116 spoken by Madarpa (N111) (1980:3). For Yolngu languages see Yolngu Matha N230.
Speaker numbers were measured differently across the censuses and various other sources listed in AUSTLANG. You are encouraged to refer to the sources.
Speaker numbers for ‘NILS 2004’ and ‘2005 estimate’ come from 'Table F.3: Numbers of speakers of Australian Indigenous languages (various surveys)' in 'Appendix F NILS endangerment and absolute number results' in McConvell, Marmion and McNicol 2005, pages 198-230 (PDF, 2.5MB).