Schebeck says that Wulkara (N93) is a 'dialect form of the name Wobulgarra' N88 (2001:96); Bowern describes Wulkara as another name for Wubulkara N88 (Bowern, 2007 p.c.).
Warner (1937:46) lists Wulkara (N93) language; Capell lists Wolgara as a dialect of Wulamba (1963); Oates and Oates (1970) treat 'Wolgara' (N93) and 'Obulgara' N88 as distinct identities. Tindale lists 'Wulkara' and 'Wolgara' (N93) as alternate forms for 'Wobulkara' N88 (1974:225).
See and use Wubulkarra N88. 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).