According to Crowley (1976:21), there is no linguistic information on this language but he suspects that a word list in Curr (Anonymous 1887) could be of Marbal as it comes from the Marbal territory. Crowley (1976, 1997) treats Yugambal E11, Ngarbal E68* and Marbal as dialects of one language, on the basis of the remark made by MacPherson (1904:683) that speakers of these three languages/dialects understood each other.
About Tenterfield (MacPherson 1904:679).
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).