Did they dress a certain way? Eat a certain way? I think of all the different tribes of America or the working classes of Europe and I can imagine certain things. But when I try to read up on the culture of untouchables specifically it seems like all I can find is,"Life SUCKED"
Did they just dress in rags and work? Or did they have an identity?
This is a very hard question to ask, not least because it touches on the deep philosophical issue of whether the "subaltern" can speak through western scholarship, an issue devised with this particular class in mind, and this apparatus makes it difficult to approach.
I don't usually just recommend a text as an answer, but in this case it might be appropriate for me to direct you to Jean-Luc Racine et al, Viramma: Life of an Untouchable, in which the co-authors try to let Viramma tell her story in her own way, presenting exactly those issues of daily life and personal identity that are difficult to approach through other scholarship.