Clark (1990, 2005) says this is part of a language continuum with Dhauwurdwurrung S20. Blake (2003) treats it as a dialect of the Warrnambool language S20 and Krishna-Pillay (1996) says it is a dialect of the same language as Keerraywoorroong S25.
The Victorian Aboriginal Corporation for Languages includes it under the Gunditjimara South West Aboriginal Language Program 'Earliest reference to dialect name: 1881 (Dawson 1881). Meaning: a descriptive name meaning 'kelp lip' taken from the broad-leafed seaweed found in abundance along the Port Fairy seashore. Clark (1990) lists 12 variants'.
Documentation on Dhauwurd Wurrung S20 may be relevant.
Port Fairy (Blake 2003:9)
Victorian Aboriginal Corporation for Languages
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).